An airship or hot-air balloon.
More example sentences
- They might be balloons, airships, planes, or tethered aerostats.
- By the way, an aerostat is a tethered balloon - they may be blimp-shaped so they're stable in the wind, though.
- He continues his work in solar and minimal powered aircraft and aerostats.
Definition of aerostat in:
- The US English dictionary