How does a glider stay airborne for hours with no engine? It makes no sense to me.

How to say “How does a glider stay airborne for hours with no engine? It makes no sense to me.” in Japanese

In Japanese

グライダーって、エンジンもないのに、飛行中(ひこうちゅう)はどうやって何時間(なんじかん)も高(たか)さを保(たも)ってるの？

Guraidā tte, enjin mo nai noni, hikōchū wa dō yatte nanjikan mo takasa o tamotteru no?

How does a glider stay airborne for hours with no engine? It makes no sense to me. in other languages