There's a website with airline bike fees. I have to search for it.

http://www.ibike.org/encouragement/travel/bagregs.htm

There's one that they update regularly, not sure if it's that one.

Bike fees seem to take into consideration that you have a moderately oversized bag. Southwest wants you to keep the bag under 50 lbs (with a 25+ pound bag alone the overall weight of my bike bag quickly hits 45 lbs) and not super oversize.

If you consider a frame is about 42" long, maybe 15-20" tall, and 6" wide, you're not going to get it into a box smaller than that. The Breakaway frames (Ritchey), S&S couplings, or a folding bike (Dahon etc) would work. A couple friends own S&S bikes. Although it's easier to fly, it's harder to reassemble the bike. I'm good with 20-30 minutes on each end to prep the bike for riding.

cdr