http://www.milliondollarbiplane.com/
Just saw this on the news here in Knoxville. A local owner/operator has made a living towing banners over local sporting events flying his 1943 Stearman. He explains on his site that because of post 9/11 restrictions, he can no longer justify keeping the plane and plans to donate it to a local charity, Remote Area Medical. RAM offers free medical care around the world and fly a pair of C-47's (or did until recently, when one broke down in Georgia, I believe).
Anyway, he has put up a webpage and is selling advertising in blocks of pixels. A few pixels have been sold and you can click on them to see the sponsor and their ad.
Dave G