How can superman fly? You can Googol all the “reasons” why Superman can fly. But in real life, everything within a gravity field will fall towards its centre, until something stops them. There are three possibilities: lighter than air objects will float in the air, boats can sail on the water, and everything else stop at solid ground. The first and second scenarios are due to buoyancy effect. How can a heavier than air object stay airborne? You need energy to offset gravity drag.