You don't have to tell me Trezeguet's strengths, I know them. For this reason I think it's fair to say Amauri is more lethal in the air. He is phisically more capable, stronger while jumping which is crucial for scoring headers. If you're comparing them with no defenders around, than yeah, Trez is probably more lethal. However in a corner hassle, you need to outjump a guy like Materazzi and I give the nod to Amauri in that case.
Trezeguet is in my opinion our best overall striker, but in aerial ability, Amauri gets the nod.