Some additional questions:

• Is it possible in the non-combat fase to convert a friendly neutral territory with only an AA-gun? I think so because it’s a land unit.

• Is it possible to cross the panama-canal with land units?  I think so because the canal lies within the territory just like the canal in Turkey. The rules don’t mention it although.

• Is it possible to cross the Danmark straight with a sub when Danmark is occupied with enemy units? I don’t think so because the rules only mention the gibraltar exception for sub crossing.