Is there any way to get Carnival to pay the $150 or would it be a losing battle???
Forget it. Unless Carnival made the air arrangements they will not have anything to do with them. This is true for any cruise line. Caveat Emptor. Did you do any on-line research before booking this cruise? The reason I ask is the Carnival website has a page with recommended flight times located here.
Frankly the self-debarkation has gotten out of control. It is ironic, but I really believe they'd move people ashore quicker if they went back to the old ways before self-debark began.