Question

What happen if we stop a helicopter in the sky for 24 hrs

Answer 1

I'm not sure what did you meant by stop( stop the engine or make the helicopter hover in a single area) so I'll take two scenarios :

Scenario 1: the pilot switches the engine off, then it will either crash land or land safely Depending upon the height it was hovering in

scenario 2: the pilot keeps the engine running, it'll remain in the same position it was in until it runs out of fuel in which case scenario 1 will occur