If you have a bike shop near you, you may be able to ask if they have any boxes that you could have. (The ones new bikes come in.) Generally, bikes are partially disassembled to be able to fit in the box. Handlebars, pedals and seat are removed, the boxes are only about 9" or so wide. We have not done it, but have heard of others doing it for flying with your bike. If you don't feel comfortable doing the work yourself, the bike shop may help you, then have the bikes shipped to the FW bike barn. I would call ahead to see if they would accept the shipment, and then help you with the reassemly. (And reshipment back home, too.)
Good Luck! and Happy Camping!