Here are the details:
Each medium/large cup has 1 coupon
32 coupons = free one way flight anywhere in the continental US
64 coupons = free round-trip flight anywhere in the continental US.
If you just purchase drinks at Wendy’s, you could get a roundtrip ticket anywhere in the continental US for roughly $80. If you don’t mind getting your hands dirty, it could be had for less. This offer is scheduled to end on December 31st, it will likely be pulled sooner.
The maximum credits you may receive per AirTran Airways A+ Rewards account is thirty-two (32), which means the maximum number of Proofs of Purchase/AirTran Flight Coupons you may submit is 128, or two free round-trip tickets.