Ok I've had this idea for a while, and thought I should post it here. I think there is good evidence that Ty Lee is a descendant of the Air Nomads.I copy and pasted my arguement from the "Ty Lee is an Airbender" thread on the Avatar forums. You can find it here: http://www.tv.com/avatar-the-last-airbender/show/28841/ty-lee-part-air-nomad/topic/13281-255361/msgs.html?page=16

1. Ty Lee joined a traveling circus (air nomad), and was doing a high wire act. Seems like a good job for an air bender.

2. Look at Ty Lee's fighting. She incapacitates her opponents by closing their chi gates or somethig like that. It seems like a very peaceful form of fighting, no one is harmed from her attacks. Most firebenders burn or kill their opponents. Airbenders are known for their peaceful ways, and would avoid killing an enemy.

3.Ty Lee is very good at jumping, flipping, etc.

4. She is very upbeat and perky, much like Aang when we first met him.

5. We haven't seen or heard anything about her family. We have about everyother main characters but hers. She may or my not be aware that she is an airbender. She may have been adopted or her parents could also be airbender (although it seems unlikely as they are supposed to be high up in the fire nation).

6. It has been mentioned she can see people's "auras". I highly doubt a firebender would have this kind of power, but an airbender havin makes sense. Airbenders are said to be very spiritual and whatnot, which could explain her odd power.