I just looked at the Harris rules, and it does say that the land units cannot retreat into a country that only a plane came from.  However, it also says that the planes can retreat, and all land units stay.  To this point, my group has used the avalon hill game rules to the word, just so we don’t have people constantly wanting to change the rules.  The rules affect everyone equally, so who really cares what they are.  However, if the larry harris rules are more specific about the ambigueities of the game rules, then maybe we’ll have to switch.

Hi , thanks alot for everyone’s answers, but I still don’t know what to think.  I think some of these rules were more clearly dealt with in previous a+a incarnations, but not in this version.  I don’t have the rules with me, but the wording of the retreat rule says that all “attacking land units” must retreat into a country that the “attacking units” came from.  The second part of the sentence doesn’t say “attacking land units”, it just says attacking units.  It could be argued that the second part of the sentence is talking about “attacking land units”, since these were what the first part of the sentence was talking about, however, I would argue that since it doesn’t say “attacking land units” in both parts of the sentence, that the second part of the sentence states that all land units must retreat together in any country that any attaxcking unit came from.  It would also require stating that the plane came through that country. 
Also, is the consensus that only the planes can retreat and then all the land units, amphibious or otherwise, would stay in combat at least until the amphibious assaulters are dead?  I couldn’t find where the rules say this, but sometimes the answer it tucked away in some corner of the rules.
Lastly, is everyone talking about the rules that come with the game?  And would the answers to these questions be different between the larry harris tournament rules and the game rules?

I have 8 British ground troops in Norway, 4 British transports able to hit Karelia with 8 more British ground troops and two bombers in Russia going through West Russia to Karlelia.  I assume I can retreat into West Russia with the Norway British troops, because the British Bombers came through West Russia, but do the British amphibious assault ground troops need to stay in battle until they are eliminated or can they too retreat into West Russia?  Is there a scenerio where I could retreat the bombers and all 8 British ground troops from Norway into West Russia after the first dice roll, while at the same time keeping the last remaining amphibious assault ground units in combat for the second dice roll, or would having surviving amphibious assault units force all units to stay in combat until the amphibious assault units are dead?

Does anyone know if you have to declare which country you are retreating into immediately, or whether you can wait until non-combat to declare?  The rules don’t seem to specify.  On the one hand, it’s part of the combat sequence which means you would have to declare before you proceeded attacking, on the other hand, logically, it seems very similar to non combat?