There are four kinds of lighter-than-air ships : hot air balloons; non-rigid blimps that maintain their shape by internal overpressure; semi-rigid blimps with a solid keel but pressurized envelope; and rigid, or dirigibles such as the Zeppelins, with aluminum frames held aloft by lighter-than-air gas in cells.
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"Piloting a blimp is like piloting no other aircraft, " said Charlie Graham, the man who would be behind the blimp controls during my two hours aloft . " Most of us are licensed to fly planes or helicopters as well, but you still need a separate FAA license to command a lighter-than-air ship.
