December 1, 1921: First flight of airship filled with helium

On December 1, 1921, the first US helium-filled dirigible made it's first flight.

"Blimp C-7 was piloted by LCDR Ralph F. Wood from Norfolk, Virginia to Washington, DC during the first flight of an airship filled with helium on December 1, 1921.

The design of the “C” model was based upon operational experience and was a decided advance over the “B”. The “C”s were 192 feet long and 42 feet in diameter, and had a streamlined car for the six-man crew. Speed ranged from 45-60 mph."