The large number of aircraft, collected for this movie, made it the thirty-fifth largest air force in the world.

Twenty-seven Spitfires, in various degrees of repair, were found for this movie, twelve of which could be made airworthy. Only six Hurricanes where found, three of which were made flyable. The Messerschmitt 109s were all retired from the Spanish Air Force. The production company bought them all, about fifty of them, and put seventeen of them back into flying condition. They are in the movie, flown by Spanish Air Force pilots, and members of the Confederate Air Force. The thirty-two Heinkels, with crews, were on loan from the Spanish Air Force, where they still were used for transport and target towing. Two of them were eventually bought by the production company and flown together with the seventeen Messerschmitts to England, for further shooting. The two Junkers 52 were also on loan from the Spanish Air Force.

Towards the end of the movie, a British Spitfire shoots down a German bomber, which then falls over central London before crashing into a railway station. This actually happened, (although the fighter used in the real incident was a Hurricane, not a Spitfire, and the bomber was a Dornier Do17 rather than a Heinkel 111). The R.A.F. pilot didn't shoot the bomber down, though. He had run out of ammo when he spotted the bomber apparently trying to attack Buckingham Palace. In desperation, he rammed the bomber, taking off the tailplane. The fuselage then crashed into Victoria Station. Incredibly, he managed to parachute to safety. His own plane rammed into the ground at three hundred fifty miles per hour. It was buried so deeply, that the authorities just left it there. In May 2004, the former R.A.F. pilot was on hand, as the remains of his aircraft were unearthed to make way for a new water main. Remarkably, part of the incident was captured on film, the tailplane fluttering down and the fuselage section (minus the wings outboard of the engines, which were torn off by aerodynamic forces) plummeting towards the ground.

The scene featuring the Polish pilots first taste of combat was based on a real event: The Polish 303 "Kosciuszko" Squadron was on a training flight with their English Commander Ronald Kellett when one of his pilots, Flying Officer Ludwik Paszkiewicz, noticed a German Dornier bomber and wanted to attack. Kellett turned him down, but Paszkiewicz attacked anyway and brought the bomber down. Afterwards, he was reprimanded by Kellett in front of the squadron, but in private he was (unofficially) commended by Kellett, who also told him the 303 was now operational. Paszkiewicz was killed in action on September 27, 1940.

Adolf Galland, the Luftwaffe pilot who fought during Battle of Britain, who later became the youngest German General at the age of twenty-nine, was hired as a Technical Advisor.

Sir Michael Caine initially thought he was too young to play a squadron leader. However, veterans of the battle told him he was actually too old for the part.

Over sixty percent of Royal Air Force Fighter Command aircraft, during the Battle of Britain, were Hawker Hurricanes. Due to the lack of Hurricanes in flying condition, when this movie was filmed, the bulk of the air-to-air combat scenes use the more famous (and better fighter) Supermarine Spitfire. During the actual battle, whenever possible, squadrons flying the Spitfire, would engage the German fighters, escorting bomber formations, while the lower-performance (but better gun platform) Hurricanes engaged the bombers. Shooting down German bombers was the critical key, since the bombers were attacking R.A.F. airfields in the first phase of the battle, and cities after the Luftwaffe changed target priorities. This movie accurately depicts the British need (and desire) to destroy bombers, to protect their air defense infrastructure, and later protect civilian targets. For similar reasons (the lack of working aircraft of the right type), Spitfires and Hurricanes are shown flying together in tactical formations, whereas in reality, R.A.F. squadrons flew one or the other type of fighter exclusively. Due to different performance characteristics, the two aircraft would not fly and fight together.

Many of the actors were too old to play pilots. In reality, most of the pilots during the Battle of Britain were only in their twenties.

When Air Marshal Göring asks what the two German officers needed to win the battle, the second officer says, "A squadron of Spitfires." That scene was based on Adolf Galland's request to Hermann Göring during the actual event. Galland confirmed in his autobiography that he never made the remark.

When this movie was released, it received generally negative reviews. Its poor box-office performance may have been partly due to recent revelations that Britain had bombed Germany first in World War II, and also because public feeling was generally extremely anti-war, due to the Vietnam War.

The scene of Göring accusing Kesselring of betrayal, as his train departed, was based on a real event. In the actual event, Göring had left in such a hurry, that electrical and telephone wires between the train and the station building, were left connected. These were broken, and left trailing from the carriage when the train departed. Director Guy Hamilton had wanted to include this in the scene, but thought it would look too comical.

Majors Foehn and Falke, the two German squadron commanders, were based on Adolf Galland and Werner Molders, two of the most famous German fighter aces of the war. Galland was on the movie set as an advisor. He almost walked out at one point because he was angry at how the Germans were being portrayed in a stereotypical manner. Many scenes were re-written and re-shot at his insistence.

W.G. Foxley (Squadron Leader Evans) was a Royal Air Force navigator, whose face and hands were badly burned attempting to rescue a fellow crew member after a bomber crash in 1944. Due to his injuries, he lost an eye and several fingers, as well as his other facial injuries.

According to the book written about the making of the movie, the production crew used more ammunition (blanks of course) to film the movie, due to the fact that directors re-shoot scenes numerous times, than were actually used in the real battle.

This movie became regarded as a patriotic tribute to "the few", that many of those involved in the production, actors, and technicians, reduced their normal fees to work on this movie. Much of the large budget went toward the acquisition, restoration, modification, maintenance, and operation of the vintage aircraft.

The movie lost ten million dollars worldwide.

During principal photography, the real Lord Hugh Dowding, ill and confined to a wheelchair, visited the set representing his office, and met Sir Laurence Olivier, who was portraying him in this movie.

The scenes at Fighter Command, were filmed on-location at R.A.F. Bentley Priory, the headquarters of Fighter Command, during World War II. Air Chief Marshall Dowding's original office, complete with the original furniture, was used.

During filming, the closed, but largely intact, R.A.F. Hawkinge was refurbished to a degree, grass was tidied up, brickwork was cleaned and re-painted. Most of the site is now a housing estate, but for a few buildings and gun emplacements, some now housing a museum, are still intact.

The Spitfires, Hurricanes, Messerschmitts, and Heinkels were repainted into authentic 1940 colors, but were so perfectly camouflaged, that they could not be seen against the ground or sky. Most of the aerial scenes were filmed with clouds in the background, so the aircraft could be seen.

Sir William Walton was hired to write the score, which would have been his last. Because of his advanced age, he turned to friend Sir Malcolm Arnold for assistance with the orchestrations (which Arnold supplied, as well as writing additional cues). Harry Saltzman rejected the score, stating it wasn't long enough. Ron Goodwin was hired to write a new score, but when told he would be replacing one of Walton's, his first reaction was, "Why?" Goodwin eventually wrote the replacement score, but Sir Laurence Olivier threatened to have his name removed from the credits, if none of Walton's original was used. For this reason, Walton's original music was kept for the "Battle in the Air" sequence towards the end of the movie.

Many mock-ups of Spitfires and Hurricanes were made in the months prior to filming. Some had lawnmower engines fitted, and could be taxied around the airfield, but if they braked too hard, they would flip up onto their noses. This happened several times in front of the cameras, and some of the footage was eventually used in this movie.

This movie takes place from May to September 1940.

The character of Section Officer Maggie Harvey was based on Air Commodore Dame Felicity Peake, who was a young section officer at R.A.F. Biggin Hill in 1940. The scene of Harvey being ordered to put her cigarette out, and Harvey yelling back at Warrant Officer Warrick, was based on a real event.

Duxford Airfield, near Cambridge, agreed for one of its hangars to be destroyed for the movie. The hangar in question, was considered unsafe for preservation. The other three hangars are still intact, and are used as an air museum.

In the real Battle of Britain, there were other German airplanes used, mainly Messerschmitt 110 fighters, Dornier 17 bombers, and Junkers 88 bombers. At the time of making this movie, there were no flying examples of these aircraft.

Most of the extras in the scenes, filmed in East London and Aldwich underground station, were survivors of the Blitz. Some of the extras pulled out, because the scenes were "too real" and brought back painful memories.

A B-25 Mitchell bomber, owned and piloted by Jeff Hawke and his co-pilot Duane Egli, was converted into a camera plane. Cameras were fitted into the nose, tail, dorsal, and belly turrets, the nose being fitted with an optically perfect dome. The plane was painted in many bright colors, so it would look different from all angles, and would be easily seen by other planes. It was nicknamed the "Psychedelic Monster". Eventually flown back to the U.S., it sat derelict for many years in New Jersey, before being restored back to flying condition in Florida. Flown in air shows for many years as "Chapter XI", referring to the high cost of flying, but later repainted as "Lucky Lady".

The Heinkel 111 bombers were in fact Spanish built CASA 2111 bombers, Heinkel 111 H constructed under license, but with Rolls-Royce Merlin engines and many other modifications. The Rolls-Royce engines were more powerful than the original Junkers Jumo, and so the planes had more performance. In fact, all of the real airplanes used on this movie, except the Junkers Ju 52 (also Spanish built CASA 352) had British-built Rolls-Royce Merlin engines.

The number of German losses (killed in action (K.I.A.)) during the Battle of Britain were tabled during this movie's closing credits. Bomber Crews K.I.A.: 1,176; Stuka Crews K.I.A.: 85; Fighter Bomber Crews K.I.A.: 212; Fighter Pilots K.I.A.: 171; Missing Crews, believed to be K.I.A.: 1,445. Therefore, according to this movie, German losses from the Battle of Britain amounted to 3,089.

When Air Vice Marshal Keith Park (Trevor Howard) first visits Squadron Leader Harvey (Christopher Plummer), a double was used in place of Howard for the shot of him jumping out of the Hurricane, because, as Director Guy Hamilton said, "You don't have elderly actors jumping out of elderly planes." Howard was only fifty-five at the time.

The white smoke from damaged engines, was made by injecting cooking oil into the exhaust manifold.

Major Falke's (Manfred Reddemann's) adjutant, (elder man in white uniform), is seen carrying an Iron Cross and an older Flight Badge from World War I, indicating he was a pilot during that war.

The Junkers 87 Stuka dive bombers used in this movie, were model airplanes filmed in Malta, the only ones not real (the Percival Proctor aircraft, which had been modified to represent Junkers 87 aircraft, were found to be too dangerous to use). Their dive-bombing technique is not very realistic. Stukas will usually dive sixty to ninety percent, and release their bombs while diving (not pulling up).

The Heinkel 111, as shown in the movie, had only three 7.92 machine guns total, placed to the rear, front, and belly. A common criticism of the HE111, during the actual battle of Britain, was that it was inadequately armed to deal with the enemy fighters. Later models added left and right machine guns.

The Blitz was ordered partly because the Luftwaffe had failed to defeat the Royal Air Force in prolonged air battles, and also because the R.A.F. had already bombed Germany since March 19, 1940. Adolf Hitler gave a famous speech outlining his reasons on September 4, 1940. Part of the speech is depicted in this movie.

Major Föehn and Major Falke are veterans of the Spanish Civil War judging by their wearing of the "Spanish Cross" badge, an award given to members of the German volunteer "Condor Legion" who fought in the Spanish Civil War on the side of Francisco Franco's government.

The closing epilogue is a famous quote from Sir Winston Churchill. It states: "Never in the field of human conflict was so much owed by so many to so few." - Winston Spencer Churchill. In some versions of the movie, the quotation differs from the above mentioned and instead reads, "This is not the end. It is not even the beginning of the end, but it may be the end of the beginning." This quote is also attributed to Churchill, although it actually referred to the Second Battle of El Alamein in November 1942.

The Jackdaw Inn, located in Denton, near Canterbury, England, featured in scenes based around the first on-screen meeting of Colin (Christopher Plummer) and Maggie Harvey (Susannah York). It also served to place the event in historical context of the story, with a muster of the Local Defence Volunteers outside.

When the Germans are marching into Dunkirk, they are accompanied by several vehicles. These are actually American: M2 Half Track Car fitted with a German MG34 machine gun, and a M37 105mm Howitzer Motor Carriage fitted with a heavy anti-tank gun instead of the regular Howitzer.

This was the first time that radio control model planes were used in a movie. Although very common these days, it was a big deal at the time, and some of the U.K.'s most skilled model builders were contacted and hired. They quit their jobs and spent several months building and preparing the models full time.

There were to have been scenes featuring Lord Beaverbrook. Sir Alec Guinness was hired to play Lord Beaverbrook, but these scenes were cut from the script shortly before filming.

Sir Laurence Olivier took just twenty thousand pounds sterling as his salary, considerably less than his normal payday.

At least two excerpts were used by Pink Floyd in their "The Wall" album: Audio from Stuka diving during the attack to the radio station is used at the end of the first song, "In the Flesh?" The scene in which Simon is shot can be heard at the transition between the songs "Nobody Home" to "Vera". The phrase "Where the hell are you, Simon?", for example, is clearly recognizable at this point.

The recently closed St. Katherine's Dock was used for some of the bombing scenes, the site of the warehouse, now being a hotel. At the time of filming, only that dock had closed in London, and it had been badly damaged during the blitz.

Houses in Peckham Rye, South London, were used as some of the blitz scenes. These houses at the time were being cleared to make way for the North Peckham and Camden Estate housing projects that were completed during the 1970s. Many of the scenes were filmed in houses while they were being demolished.

The Royal Air Force bombed Berlin at least six times, from August 25, 1940 until September 4, 1940, not just once as shown in the movie.

The planes used as Bf 109s were actually Spanish Hispano HA-1112 Buchons. Basically a Bf 109 with a Rolls-Royce Merlin engine, the nose of the plane looks completely different that of a German Bf 109.

In April 2017, it was announced that Ridley Scott would be directing a new version of this movie for Twentieth Century Fox, with Matthew Orton performing screenwriting duties.

Timothy Dalton auditioned for a minor part as a Royal Air Force pilot.

In the beginning of the movie, there is a scene with a beach filled with abandoned equipment and weapons. This scene is meant to show the aftermath of the Allied retreat from Dunkirk and the French mainland.

Trevor Howard replaced Sir Rex Harrison at the last minute.

Roger Ebert gave this movie one of his worst reviews.

The character that Harry Andrews played is called Senior Civil Servant in PR and cast lists. He is called Sir Austin Stokes in paperwork regarding the production.

Several scenes from the German side were shot in Spain, and Spanish extras were used for portraying soldiers and ground crew.

In addition to the camera plane, the production also made use of a helicopter. No gimball mounts in those days, just people like Camera Operator John Jordan who hung under the helicopter in a parachute harness. He died before this movie was released, in May 1969.

If the Battle of Britain had been lost, the Kriegsmarine did not have the ability to get past the much larger Royal Navy. In the event of a successful invasion of the U.K., the Royal Navy was to continue the war from Canada.

Adolf Hitler told his Generals on August 14, 1940 that he would not attempt an invasion of the U.K. The German High Command had begun planning the invasion of the Soviet Union in early July.

In his memoir "The First and the Last" Adolf Galland wrote, "The theme of fighter protection was chewed over again and again. Goering clearly represented the point of view of the bombers and demanded close and rigid protection. The bomber, he said, was more important than record bag figures. I tried to point out that the Me109 was superior in the attack and not so suitable for purely defensive purposes as the Spitfire, which, although a little slower, was much more manoeuvrable. He rejected my objection. We received many more harsh words. Finally, as his time ran short, he grew more amiable and asked what were the requirements for our squadrons. Moelders asked for a series of Me109's with more powerful engines. The request was granted. 'And you ?' Goering turned to me. I did not hesitate long. 'I should like an outfit of Spitfires for my group.' After blurting this out, I had rather a shock, for it was not really meant that way. Of course, fundamentally I preferred our Me109 to the Spitfire, but I was unbelievably vexed at the lack of understanding and the stubbornness with which the command gave us orders we could not execute - or only incompletely - as a result of many shortcomings for which we were not to blame. Such brazen-faced impudence made even Goering speechless. He stamped off, growling as he went."

The unsafe hangar at Duxford was blown up twice. The special effects crew had underestimated the necessary amount of explosives. After the second time, as the dust was settling, Director Guy Hamilton called out, "All right everybody, one more time!"

When German fliers are seen to jump from their aircraft they are use parachutes of an Allied design. German parachutes had suspension lines that are joined above the airman's head and allied ones appear to eminate from either shoulder.

This movie ignored the Italian involvement in the battle.

Living in towns near North Weald, it became common to have Spitfires fly over quite low while playing in the school playground during the making of the movie. Consequently, "Battle of Britain" trading cards were banned in school so as not to offend teachers and staff who had taken part in the war.

American Special Effects Creator John P. Fulton was going to do the special effects for this movie. However, he died in England before principal photography began.

The documentary, The Battle for The Battle of Britain (1969), revealed that the main camera plane had CCTV on all cameras, with video recording for instant playback. Video recorders had only been around for ten years or so, and were very expensive.

This movie was received very badly in India, which had been under British occupation during World War II.

This movie was released at a time when anti-war feeling stirred by the Vietnam War was running high, together with cynicism amongst post-war generations about the heroism of those who participated in the Battle of Britain. It was generally dismissed by critics.

The goggles used in this movie by the British pilots,were the MK VII version of the Royal Air Force issued items, however this version was not released to pilots until 1942, too late to be used during the Battle of Britain. The same mistake was made in Dunkirk (1958), which occurred just prior to the Battle of Britain.

Winston Churchill was going to release many deadly chemicals, including anthrax, in the event of an invasion.

Isla Blair (Mrs. Andy) has said in interviews a huge chunk of her part was cut from the final print.

Christopher Plummer (Squadron Leader Colin Harvey) and Sir Laurence Olivier (Air Chief Marshal Sir Hugh Dowding) played Arthur Wellesley, 1st Duke of Wellington: Plummer in Waterloo (1970) and Olivier in Lady Caroline Lamb (1972).

This movie portrayed the traditional view that the Axis lost the battle because of the switch to bombing cities. However, this theory has been widely debunked as an urban myth.

When this movie was released, there were were complaints that it was racist.

Cuts turned Sarah Lawson's role of the Skipper's Wife into a non-speaking one.

Ian McShane and Isla Blair share the same birthday (September 29).

In 2012, Producer Graham King hired Screenwriter Robert Towne to write a screenplay for a proposed remake.

There were simultaneous World Premieres of this movie on the evening of Monday, September 15th in London, and several other U.K. cities, including Birmingham, Manchester, Newcastle, and Glasgow.

(At around one hour and twenty-two minutes) The instrument being used is a pair of German Luftwaffe 25 X105 Doppelfernrohr aircraft identification and general observation binoculars.

Edward Fox, Kenneth More, Sir Laurence Olivier, Sir Michael Redgrave, Sir Ralph Richardson, and Susannah York appeared in Oh! What a Lovely War (1969).

The title shown on-screen at the beginning of this movie is "The Battle of Britain". However, on advertising posters it was just "Battle of Britain".

Sir Michael Caine tells in his biography that there were severe arguments with the German former Luftwaffe pilot Adolphe Galland, who served as a Technical Advisor for this movie. Galland maintained that Luftwaffe did not really lose the Battle of Britain.

When Göring arrives at Pas de Calais via special private train, the anti-aircraft gun platform on the German train is actually a U.S. Military M45 Quadmount .50 caliber weapon system. The proper defensive platform would be a German 20mm or M38 machine multi barrel gun platform.

When " Battle of Britain" was first shown on British television, on BBC1 on Battle of Britain Sunday in September 1974, it was watched by over 24 million viewers. There were only three channels at the time.

Features three Academy Award winners: Sir Michael Caine, Sir Laurence Olivier, and Christopher Plummer; and five Academy Award nominees: Trevor Howard, Sir Michael Redgrave, Sir Ralph Richardson, Robert Shaw, and Susannah York.

Robert Shaw and Christopher Plummer appeared in The Royal Hunt of the Sun (1969).

Robert Shaw and Karl-Otto Alberty appeared in Battle of the Bulge (1965).

Director Guy Hamilton, Robert Shaw, and Edward Fox worked together again on Force 10 from Navarone (1978).

Rank first tried to get " Battle of Britain " into production in 1966, but it fell apart due to budgetary concerns. Paramount then came on board, but they too had pulled out by early 1968, for the same reasons. It was only when Harry Saltzman came on board that United Artists agreed to back the $12m war epic.