Jake Cutter flies Cutter's Goose which is a Grumman Goose G-21 painted red and white.
The series takes place in 1938 with some flashbacks to 1937 and 1936, and repeated references are made to the fact that Jake flew with the American Volunteer Group or "Flying Tigers" prior to his adventures in the show. The only problem is that the AVG did not see its first combat action until December 20th 1941 (that's three years after the events in the series are supposed to have taken place). We also see at least one flashback of Jake as a Tiger, fighting Japanese "Zeros". The Mitsubishi A6M. or "Zero" never fought against the AVG. Japan sent 15 Zeros to China in 1939, before the Tigers existed, two were shot down and the remaining 13 were recalled prior to that attack on Pearl Harbour, two weeks before the AVG saw its first combat action. The AVG only fought Ki-27 "Nates" and Ki-43 "Oscars". They shot down 290 of them.