The yellow biplane trainers are Naval Aircraft Factory N3Ns. In one sequence Flynn taxis out in a big-tailed N3N-1 and takes off in a smaller tailed N3N-3 (also different landing gear struts.) Additionally, the "N3N" stunt flying is done in a civilian Travel Air painted yellow.
Anthony passes out during the high altitude chamber testing, and putting on his oxygen mask knocks off the oxygen sensor clipped to his left ear lobe, yet the next view of him from the front, still adjusting the straps, shows the oxygen sensor still attached to his ear.
In the opening scenes showing pilots manning their planes, several bi-plane fighters are forward of the dive bombers. Later when the dive bombers take off the fighters are not shown taking off before them, nor are they visible on deck.
During the high altitude pressurized cabin test, after the pilot Joe Blake (Fred MacMurray) passes out and the plane goes into a dive, the plane shown spinning and diving out of control is a shiny dark green plastic toy with no markings, while the actual plane shown flying in earlier views of the test is a lighter military green in color and has U.S. Navy markings on it.
The airfield used in the beginning of the movie was never identified, nor does it look like Ford Island which was the principal field used by the Navy. The mountains depicted in the backdrop are a matte painting and the scene was likely shot during location filming in San Diego.
When Regis Toomey as Lt. Tim Griffin, USN, comes back into the story as an RAF pilot flying a supposedly Royal Air Force Fighter, it is nothing of the kind. It is an American Ryan STA Trainer with RAF-style camouflage & markings, a covered front cockpit and a cobbled-on radial engine cowl.