Got some old airplanes lying around collecting dust? How about some flavored ground beef from a new burger offering that didn't go over well? Don't worry, because there are a few agencies out there that can help you trade your impaired assets for ad space. The practice of finding a buyer for a marketer's distressed assets and trading them for media credits that are subsequently used to fund media buys is by no means new -- nor is it without stigma. But one feature of recession-era media economics has been that the barter business has gotten bigger.