My vote goes to...
The Great Waldo Pepper!

There was some FANTASTIC actual footage in real life period aircraft with real life old timer barnstormer pilots flying them. Many of the pilots that did the stunt flying for that movie were authentic real life barnstormers and stunt pilots from the 20's and 30's. The last of the breed.

No BS blue screen scenes here. And very little in cut in fake stuff. I only wish that Hollywood could figure out how much better these films were than the crud they try to pass off in modern pictures.

YouTube - DOGFIGHT WITHOUT AMMO - THE GREAT WALDO PEPPER 1975

Honorable mention goes to "The Blue Max" another film with tons of real life flying in some very well done replica and real period aircraft.

YouTube - THE BLUE MAX(1965) Original Theatrical Trailer