Lobo, hope you see this. . . Couldn't e-mail the info. directly cuz you haven't yet posted a home page with your address. (Do it.)
Jim Butt did a great article about constructing just the sort of PVC small sub carrier Tim is talking about above. It's in SCR issue #38 (September, 1999). I did my own article about traveling by air post-9/11 with one of Jim's carry cases. It ran in SCR issue #50 (September, 2002). If you don't want to buy these back issues and have no access to local members willing to loan 'em, lemme know and I can snailmail photocopies.
P.S. I still air travel annually with my Blueback in her case and have been fine. I no longer take it as a carry-on though; I pack the case in a cardboard box as if for shipping and check it along with my transmitter/rechargers in their own aluminum carry case. I find this quicker and easier than dealing with the inevitable Security Inquisition, and yet still have the carry case at my destination to transport the boat easily from hotel to run site. Last advice: pack your WTC separately in the big cardboard box when flying. Carrying it within the hull inside the case (at least for the air leg) offers great potential for hull damage if it's handled roughly by airline baggage types. Once back in your own careful hands, you can again transport the complete boat -- WTC within the hull -- via the carry case to the site. (The voice of experience.)
Good luck and see you in Carmel. Perhaps we can patrol together at some point . . .
Sure writing is easy: just sit staring at a blank page until the drops of blood start forming on your forehead.