This is the final part in a series.

As the summer of 1925 began, the United States possessed two airships, each over two football fields in length. The German-built Los Angeles was designed to show the commercial use for the giant airship while the U.S.-built Shenandoah would demonstrate the military possibilities.

A shortage of helium, the lifting gas, meant that only one could fly at a time, so when the Los Angeles was forced into the Lakehurst hangar for an overhaul, the Shenandoah was pressed into the peaceful role of spending…