Yes it’s a really good question, Ichabod. I’m going to add this one to my “Know the Rules” video series.
My apologies leatherneckinlv for being short with you. It honestly is written differently in both rule books. I don’t take the Political Situations from the Pacific or Europe sections of the rule books, I get them from the Global rules contained in both. You would think they would both say the same thing but they don’t. I will show both rule books in my video and you can see the difference. Now that I know that I will be sure to check both books first before I try to interpret a rule.
As far as the island question, Simon’s post at the top of this page shows clearly that you can’t place units on those empty land spaces that aren’t labeled. Even if you could make the argument that an airbase wasn’t a unit and place one there, you wouldn’t be able to land any planes (they are units) there and it would be a waste of 15 IPC.