The Victorinox Jetsetter Swiss Army knife features the classic multi-tool design, only there is no knife blade so it is airplane friendly. But with seven useful implements, you won't even notice it's gone. It has a closed length of just 2.25" that is compact enough to fit comfortably in a pocket or attach to a keychain. This Victorinox model has a red handle with the classic Swiss Army logo.
Comes with a lifetime warranty against manufacturer's defects.
While these are great to have something sharp on a long flight, and you can take them past the TSA checkpoints in the US, DO NOT plan to do it in foreign airports. I've had one taken in Europe and one in Australia. It seems foreign governments don't trust you with a "tool" on board.