First of all, as the FBI says: "Eyewitnesses are the worst witnesses",
Then of course there is the fact that he might not even have said a joke at all, but is being misunderstood, When the crew (air marshall) inquires you, it goes in such a hurry you get no change to answer at all... so where did you got that pipe from, he might (not sure of course I wasn't there) have said he carried it in his shoe... On the other hand it can also be a test to see how easy they can get through securities.. We probably never get to know....