Popeye is celebrating the Fourth of July by arranging a patriotic garden, while his nephews (although only two are present in this short) would only want to play with fireworks. However, Popeye takes the fireworks away and locks them in a shed, opting for safer activities. The boys try to trick him into playing baseball so they can send the ball (and him) away, then use a hornet’s nest against him, to no avail. When he gets into his car for a ride, his nephews tie a rope between it and the shed, sending its wreckage to crash into the car. The two boys are finally able to light their fireworks, but this causes various accidents to happen to Popeye, and them to be thrust up into the sky. By eating his spinach, Popeye gains the ability to fly by pipe propulsion. Saved just before the rocket that is hauling them up explodes, the kids finally settle for the safer yet still noisy game of bursting balloons.

Source: http://popeye.wikia.com/wiki/Patriotic_Popeye