Quick trivia question to start off the post: which of the below two routings looks like it wouldn’t be permissible as a one-way award reservation with American?
Routing 1:

Routing 2:

Well, I think it’s pretty obvious that the answer should be routing 1, though in reality it’s routing 2 that isn’t allowed with American.
American simultaneously has the stingiest and most generous award routing rules, as I discussed in great detail in this post. They’re extremely generous because they’ll let you exceed the MPM (maximum permitted mileage) for a city pair by up to 25%. That’s more generous than just about any airline. At the same time they don’t let you transit a third region when traveling between regions, even if it’s the most direct routing imaginable. They’ll only let you transit a third region in the following instances:
To/From Via
North America to/from Indian Sub Continent/Middle East can connect in:Europe
North America to/from Africa can connect in:Europe
North America to/from Asia 2 can connect in:Asia 1Central/South America to/from Indian Sub Continent/Middle East can connect in:Europe
Central/South America to/from Africa can connect in:Europe
Central/South America to/from South Pacific can connect in:S. America 2South America 2 to/from Indian Sub Continent/Middle East can connect in:Europe
Indian Sub Continent/Middle East to/from Asia 1 can connect in:Asia 2
Indian Sub Continent/Middle East to/from South Pacific can connect in:Asia 2Africa to/from Asia 1 can connect in:Asia 2
Asia 1 to/from Europe can connect in:Asia 2
Asia 1 to/from South Pacific can connect in:Asia 2
Compare that to United, which will let you route from the US to Asia via Europe or the US to Australia via Asia, or US Airways, which will… okay, let’s not kid ourselves. They’ll allow you to route between any regions through just about any region.
The most frustrating example of American’s region policy has to be traveling from the US to South America zone 2. They won’t let you transit South America zone 1, where LAN has a hub. So in other words you couldn’t fly from Buenos Aires to Lima to New York on a one-way AAdvantage award, while you could fly from Buenos Aires to Santiago to New York on a one-way AAdvantage award, even though it’s a longer routing.

It’s instances like this that drive me nuts about redeeming American miles. Routing via Lima makes sense. The total travel distance is 5,584 miles, while the MPM plus 25% is 7,951 miles. So that’s nearly 2,500 miles under the maximum number of miles that could be flown on such an award.

At the same time, LAN’s published fares between Buenos Aires and New York allow routings via Lima.
Yet because Lima is technically in “South America zone 1,” it requires two awards.
So pardon my rant, but c’mon American, I love you guys!
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