The American player used his planes from the aircraft carriers based in the sz 33 to attack the Japanese Fleet in the Java sz, assuming that the USA fleet can kill off the 2 blockers and move the carriers to seazone 45 to give the planes a place to land. If the blockers were not destroyed, there would be no place to land. Is this move allowed?
Planes are allowed to attack if, assuming that all attacker rolls hit, and all defending rolls miss, that every plane has a possible landing space after noncombat moves. So yes, they are allowed to attack as the carrier could move to provide a landing zone in the event that they destroy the blockers.
If they fail to destroy the blockers, the planes no longer have landing spaces and will perish. But it’s still a legal move, as there was a CHANCE that they would succeed.
Secondly, after the attack went though, all the planes were destroyed, would the carriers be forced to move to seazone 45 regardless of whether the planes survived or not?
No, the carrier is only required to move if you need to provide a legal landing space for a plane. If a plane survives, you MUST move to pick it up. But if there are no surviving planes, you can move the carrier as you will. Same deal with purchased cariers: if the planes don’t survive to return to the seazone adjacent to your factory, you aren’t still obligated to place that carrier in the seazone that the planes were meant to return to.