I wouldn't call myself full on claustrophobic - but I'm just not a fan. I've only been stuck in one once - but that just sucked so bad. I always take the stairs when I have an option.
Airplanes as well - and not flying - flying I could care less. Goes back to the claustrophobic part I suppose. Once we are in the air I'm good to go as I know we are on our way and once we land you usually have very little delays getting to your gate to get off the plane - it's the sitting and waiting to take off - I don't like being cramped and told I can't move, can't stand up, can't go to the bathroom etc...and they never give you information if you're behind your "take off" time since as long as you back away from the gate you are an "on time" departure.
I once sat on the runway at La Guardia for 90 minutes waiting in a line of like 10 planes to take off - I didn't even care about the delay - it's about feeling trapped because of FAA regulations when you are away from the gate.