That does help a lot; thanks to all who responded to my questions!

So, in other words, the aircraft can only fight in one battle per turn? It can’t land on an adjacent territory owned by its own country that is in the process of being invaded  by the enemy?

If an aircraft carrier has been destroyed by a submarine and has a fighter left, can the fighter move into a territory that its country controls even if said territory has been invaded?

For Example:
A British force invades German controlled Libya. During the same combat movement, a British submarine attacks a  German carrier off West Africa. The sea battle is fought first. The German carrier is sunk but the plane survives. Can the surviving German fighter land in Libya and take part in the battle there?

Thanks in advance for your help!