Originally Posted by Luubert
They do offer the booking code though. (usually G) So if its a Tango code than it's a Tango fare.
Expedia advertises Tango fares, and has been for awhile... got dinged 2,047 status miles when I inadvertently booked myself on a Tango flight. On Expedia, you can go to the "Fare rules" page and see what you're booking. Look for the FN or TG at the end to let you know what kind of flight you're taking.
A problem with Expedia is that it will give you only the cheapest AC option, which is usually Tango. So, you have to be careful with what you book there or book at AC to know what you're getting. I need to see if the developers here are planning to offer an option to book a flight with 100% miles...