It has a fibreglass frame and a 200ft line; once airborne, it will maintain altitude in the gentlest of breezes.

Type could not maintain altitude on single powerplant.

The weight had been miscalculated and, during the flight, the aircraft could barely maintain altitude.

In reality, all fixed-wing aircraft glide naturally, and the engines serve only to maintain altitude during the flight.

Twin-engine types could not maintain altitude with an engine out, unless they were so overpowered that the airlines could not afford to operate them.