Keep in mind that wind isn't in any way limited by the speed of sound... Speed of sound limits the speed that a perturbation moves within a medium, whereas with wind the medium itself is moving. It's like putting a big aquarium on a train basically, but with air instead of water. The fish wouldn't know the difference. It does mean however that an aircraft flying against the wind would basically have to go supersonic in order to move forwards and not backwards in relation to the ground.