The identity of the enemy planes never are never revealed by the captain, gunfire muffles what he says. They do resemble German models, including the large seaplane.
Popeye and his commanding officer are back, but under actual wartime conditions. Jack Mercer, who voiced Popeye, would also see active duty during the war.
Popeye is shown reading the Superman comics. Jack Mercer, Popeye's voice, also provided supporting characters in the Superman shorts of the wartime era. These were produced by Famous Studios, too
Mosquito boats in WW2 were also known as PT boats. Small, swift, and capable of delivering a payload of destruction.
The destroyed ship carries the sign V for Victory, a WW2 slogan that would have resonated with cinemagoers.