While pals Skinny (Donald Haines), Danny Graham (Bobby Jordan), Peewee (David Gorcey), Algy Reynolds (Eugene Francis), and Scruno (Sunshine Sammy Morrison) all work at the Reynolds Aviation Company, which is run by Algy's father (Herbert Rawlinson), Muggs (Leo Gorcey), the only one of the kids who refuses to work, spends his time flirting with an ambulance nurse named Helen (Joan Barclay). Helen, though, is in love with her test pilot boyfriend Tom (Dave O'Brien). One day, when Tom's plane crashes onto the plant airstrip, Reynolds suspects that the crash may have been the work of saboteurs. Later, on the airfield tarmac, Muggs jokingly appoints himself as the new operator of Dr. Richard Nagel (George Pembroke)'s ambulance plane and gives his pals a tour of the aircraft. Their playful games are soon brought to a halt by Nagel, the secret leader of a spy ring, who catches the boys on his plane and angrily orders them off.