Since its only in the cups themselves. All of the Wendy restraunts should have received a shipment of cups for this promotion. Unless they only shipped them out to cities that have flights that airtran offers.
Example, Chicago is one of their listed cities so they have cups here for it. But perhaps cities that aren’t in their listed flight routes won’t get the cups… perhaps. But just goto a wendy’s and order a medium drink and see if the design of the cup is different. If it is then you’re good to go. If not then maybe you’re not in luck :(.