I just took the player script.
the problem is my gale uses platforms floating in the air.

How to aoid theplayer to make infinite hight jumps ?
Because the actual C trace just needs i think some ground ?
It is possible to jump from aerial platform to another without that infinite jump problem ?

Just let the player jump again if the c_trace is <4 (or something similar). Otherwise forbid it (use a variable or reassign your jumpkey to NULL).