I've been traveling a lot recently.  At several airports I've visited, there have been very nice collections of model airplanes.  Everything from 1:72 up to 1:3 or 1:2.
One of the better collections was in Albuquerque with roughly 200 or so donated model airplanes.  Varying qualities, but some were really quite nice.  Unfortunately, I didn't have a camera with me.
SFO has some large scale models (Spitfire and a Hurricane) hanging in the domestic terminals.  (They also have a very nice electronics prototyping/ergonomic design display).
I'll try and start taking pictures if I'm on time ( 

 ), but was wondering if anyone had any airports to recommend looking around.  (Especially if you're stuck for a few hours)