The parrots in the quarantine section are very obviously stuffed birds. They do not move at all during the tracking shots in that section.
What's the trouble, Captain?
Captain Brent: I'm not happy about the port outer - she sounds a bit rough to me.
Nick Millbourne: Instruments check all right?
Captain Brent: Yes.
Nick Millbourne: The instrument say she's okay, the chief mechanic says she's okay...?
Captain Brent: Young man, let me tell you something. In the air, I am...
Ealing built one of its largest ever sets to represent the interior of the newly built Europa Building in the central area of what was then known as London Airport. However, this terminal, as its name implies, served only short haul airlines, long haul services used the temporary structures alongside the A4 Bath Road (known as "North Side") until the Oceanic terminal (later renamed Terminal 3) opened in 1961. Thus there would have been no BOAC personnel (or passengers) in the Europa building, as portrayed in the film.