Normal human beings don't joke about planting a bomb on an airplane.
That's pretty funny. Normal human beings make jokes about boarding an aircraft these days all the time (see the post after yours) -- They just don't do it within earshot of a TSA person, an airline employee, a cop, or in the airport terminal. I'll bet even you make jokes about it -- at the appropriate time, of course. This perp's problem was that he was unable to discern that it was not an appropriate time or place to voice his dumb joke.