Factual error: The aircraft are definitely post-WWI. Biggles is flying a De Havilland Tiger Moth, which appeared in 1930s. The German fighter is probably the PT-23 Stearman.
Biggles (1986)
1 factual error
Directed by: John Hough
Starring: Peter Cushing, Neil Dickson, Alex Hyde-White, Fiona Hutchison
Continuity mistake: The film is supposed to take place in 1917, but several of the german soldiers our heroes encounter are armed with Bergman M18 sub-machineguns which didn't appear until a year later. To make things even worse all the guns comes with a magazine-type that didn't appear until the mid-thirties.
Biggles: Quick! Untie us before they realise you're not a God, you're just an American.
Question: How was Biggles able to land the helicopter on a moving train despite only just learning to fly it?
Answer: It would be virtually impossible for a novice pilot to be able to do this.
raywest