Blimps
Most untethered blimps, balloons, and dirigibles require a large amount of power to fight the wind, and the weight associated with a pilot and cockpit means that only very large vehicles with powerful internal combustion engines have been practical in the past.
[edit] Indoor toy
Take a mylar balloon and add small propellers. You now have a blimp - albeit one that can only handle a few centimeters per second of wind.
[edit] Indoor aerial photography & advertising
Stadium aerial photography and auxilliary billboard space was the lucrative mission of some of the only commercial manned blimps that remained operational through the late 20th century, such as the Goodyear Blimps. Now that electric RC and UAV capabilities are viable, using much smaller airships is practical, but a side effect of making them smaller involves being less able to fight the wind. Positioning them in indoor stadiums & arenas where they don't have to fight the wind has made RC blimps a very visible presence in some sports.
[edit] Hyperblimp
In a series of 2006 Youtube videos, Daniel Geery showed the potential of a long cigar-shaped design constructed from two gores of stretchy transparent material. These 'Hyperblimps' are agile and capable of quite high speed using fixed fins and a pair of two-DoF vectored-thrust electric motors on the nose and tail. Long, streamlined shapes are the only LTA designs that can efficiently penetrate a steady wind without being massive. Hyperblimps and adaptations of hyperblimps are strong candidates for autopilot conversion due to their endurance. They're also strong candidates for solar power conversion.
Geery has created a company around building large hyperblimps, and has seen interest in police departments.
