AIRLANDER: world's longest airship. Actually it's fairly old technology; it was developed in England, bought by the U.S. Army to test heavy-lift capabilities, canceled when budget limitations ended Army involvement, and returned eventually to England.

Lockheed Martin was involved in a similar venture in the late 1990's; it too, got canceled when it became obvious it was not a commercially viable enterprise.

Nevertheless its sheer size excites the imagination; I hope it succeeds.