How bats use sound to help them fly?

Bats use sonar to sense their surroundings. Sonar works by the bat making a high-pitched call and listening to the echo from nearby objects. So bats definitely do make a noise when they fly. Also, a bat's wings are not designed for stealth, so even if you do not recognise a bat's sonar call, then you would hear the wings beating when a bat flies close to you. In reality, nobody really thinks about the noise of bat's wings because of the noisy call.