Quoted from Reader's Digest:

        When I played with a symphony orchestra, our union reached 
an agreement with a major airline about which instruments we could 
carry on board, and which had to be shipped as luggage.  A cellist 
was dismayed to find that his delicate, expensive wood instrument
was consigned to the rougher handling and cold temperatures of the
baggage hold.
        He neatly solved the problem.  Cello in hand, he approached
the flight attendant at the gate and asked, "May I bring my clarinet 
on board?"  Scanning her list, she replied, "Clarinets are okay.
Have a good trip,"  and, smiling, waved him on.