I have the one-step lower model, the GorillaPod SLR Zoom, with the Joby BH-1 ballhead. It's small, light, and holds a gripped body and standard zoom just fine. I bring that when I don't want to pack my 4-section CF tripod.

FWIW, that tripod does fit in a carryon hard case (Storm im2500) with the head removed. I've taken it on flights with no airport security issues (and I've taken a CF monopod in carryon instead, on some occasions, also hassle-free). YMMV.