His aircraft was unable to sustain flight.

Unable to sustain flight, he was managing no more than a downward spiral.

But it was not designed to sustain atmospheric flight.

The plane was to be powered by ten jet engines clustered around its nose and was expected to sustain flight for six minutes.

Even if he could sustain flight now, Mail's strong grasp was keeping him grounded.

This gas, if inflated into a relatively well-sealed silk envelope, could sustain flight nearly indefinitely.

This ensures the Oryx sustains flight with very little crew input, during such an emergency.

Although it has wings, it is unable to sustain flight.

The plane was flying at an altitude which was too high to sustain flight with only one working engine under those conditions.

They can sustain flight by five to six weeks of age.