"Mosquito Squadron", from 1969. There were still a bunch of the old birds still air worthy, and they make the centerpiece of the film. Plus major roles played by David McCallum (Man From U.N.C.L.E.) and Charles Gray (You Only Live Twice, Rocky Horror Picture Show). And Suzanne Neve who I'd not seen before, but who is quite dishy here.
A film like this could never be made today because it is unapologetically patriotic and portrays the military in a positive light. It was made 24 years after V-E Day, and so the equivalent for today would be a film about the first Gulf War. Indeed, we did see one of those made, but of a very different flavor towards patriotism and the military.