"The Dam Busters", upon which George Lucas leaned heavily in "Star
Wars", is black and white, but better every time you see it: from
four-engine Lancasters screaming over the countryside at night at sixty
feet, to clocks ticking in the bedrooms of dead aircrew after the raid
on the German dams; Richard Todd, who plays the squadron's leader,
dropped in to Normandy as a paratrooper on the night of 5-6 June 1944.
Not too long;

The "Spirit of St. Louis", in which Jimmy Stewart, who flew bombers in
the European theatre, plays Charles Lindbergh, who flew P-38's and
other aircraft in the Pacific (as well as a small, silver single engine
airplane across the Atlantic!). Color.

"Twelve O'clock High" (the movie, not the tv series). Black and white,
relatively short.

"The Right Stuff", especially the parts in which Chuck Yeager,
wonderfully played by Sam Sheppard: 1. launches in a B-29 and breaks
the sound barrier in the X-1; 2. launches in a later development of
that airplane and breaks the canopy with his head; 3. launches in the
NF-104 in going for the altitude record, and breaks it (the NF-104).
Long, though.

If you want to stretch the definition of "movie" a bit, "Piece of
Cake", a mini-series about the summer of 1940 which was shown on PBS
about ten years ago, is now out on DVD. It has long, loving sequences
of Spitfires flying off grass fields, landing on lawns of country
houses, flying under bridges, and arcing through the skies after 109's.
This would probably be way too long, though (about six hours).

All of the above would be PG, as I recall, with "Piece of Cake" perhaps
being PG-13.