First of all, each airline sets its own policy. However, back in
February, 2006, the TSA in Miami Fl detected my inflatable's gas
cartridge, checked their rule books and informed me that it was a
prohibited item. I had to check a bag with my inflatable and my
wife's. This happened after having carried inflatables on-board
several times. I always camoflaged them with as much other
recognizeable stuff as possible--batteries, laptop ac adapters,
cameras, etc. Maybe the TSA did not see the cartridges or maybe they
just ignored them or maybe they thought the cartridges were
permitted--I don't know. At any rate, the DID prohibit them in Miami
in Feb.

Peter
s/v Now or Never!