If it moves through the air, it creates turbulence.
If it creates turbulence, that generates sound.
An Air-raft would be as noisy as, say, a non-moving jeep in a windstorm.
An enclosed a/r would be as noisy as a sedan or minivan in same windstorm.
Before accounting for electrical system hum, interior ventilation fans, stereos blaring, sonic booms, etc.