@calvinhobbesliker:
Oh right, I forgot about transports escaping combat…
Are you allowed to assault with one infantry and leave the AAA on (until noncombat)?
Yes. That’s possible when the AAA was loaded in an earlier turn. HOWEVER - the AAA is stuck on the transport and can NOT unload in noncombat, because that transport already unloaded earlier in the turn (the infantry in amphibious assault in the combat movement phase)
In general, if you have 2 units on a transport, can you unload one during combat and unload the other in noncombat or not even unload the other at all in that turn?
First, after a transport unloads, it is DONE, as I said previously. You can NEVER unload one in combat and the other in non-combat.
You CAN unload only one unit out of two in an amphibious assault ONLY when one or both units were loaded previously. This is because the rule requires that if you picked up units in a combat move and then conduct an amphibious assault, ALL units that boarded in the combat move MUST unload and participate in the amphibious assault.
So there is a reason to leave units on transports at the end of your turn. Many times players leave one unit on a transport, so that they can pick one unit up and drop it off in amphibious assault while leaving the previously loaded one on board so the opponent can’t kill it on the newly taken territory.