The aircraft is seen approaching Rabb and Watson from behind and they hear the sonic boom before the aircraft flies over. This is the incorrect order. With the plane flying 6 times the speed of sound, the sonic boom trails well behind plane. At this speed the aircraft would far past the point where the sonic boom is heard.
Rabb clearly says he had a "P-17 Stearman" model as a kid. As an owner of a Stearman, he should know that it is a primary trainer, or a "PT-17". A P-17 was a Curtiss Hawk.
While Mac and Sturgis walk and talk outside with MGen. Kulik at Camp LeJeune, they fail to walk in step with the general, thereby committing a minor breach in military etiquette.