Some travelers apparently like United Airlines' "Fly the Friendly Skies" banners enough to carry them as luggage.

Chicago-based United is expanding an "upcycling" initiative turning old banners and billboards hanging in airports including O'Hare International Airport into travel accessories, said spokeswoman Maddie King.

"Rather than put them in landfills, we decided to try to find something creative to do with them," she said.

Last year, the airline worked with students at Columbia College Chicago and the Re:new Project to make 100 carry-on backpacks and duffels out of the banners. They sold out in two hours, King said.

This year, 750 luggage tags, drawstring bags and messenger bags will go on sale at www.unitedshop.com on Tuesday. United switched to a new partner, Relan, that is better able to handle the larger order, King said. Mendota Heights, Minn.-based Relan helps companies turn old marketing materials, like banners and billboards, into recycled bags and accessories.

Last year, profits from the recycled luggage sales benefited Glen Ellyn nonprofit Re:new and the Alto Mayo Forest Carbon Project in Peru.

This year proceeds will go back into the project so United can keep making the upcycled accessories, King said.

United isn't the only airline trying to turn at least some of its castoffs into new products. Portland, Ore.-based Looptworks said it's turned 80,000 old Southwest Airlines seat covers into leather bags and wallets in familiar shades of blue and tan, and has a similar line made from Horizon Air seat covers.