If there's enough business, contact the airline and see if they are willing to work out a charitable arrangement. I think most all of the airlines have a department that handles this, takes the proposals, approves or not, etc.

Most have some of their guidelines online, for example US Airways has a page at

usairways.com/corporategiving

They all get a ton of requests, so it's a long process for them to go through them all, it's like applying for grants usually with a window, etc.