William Lucking as Gandy Dancer appears only in the opening flashback, which chronologically predates his previous appearance in Legends Are Forever (1982).
In the opening dogfight scene, Jake's P-40 Warhawk has this teardrop shaped thing braced onto its underside. That was an auxiliary fuel tank. On patrol, you cruise around looking for enemy planes and when you find one you still want enough fuel to last through the dogfight and the trip home. But extra large fuel tanks screw up speed and maneuverability. So, cruise on the fuel in disposable auxiliary fuel tanks and if you get into a dogfight you can detach the extra tank.