I came across this on Yahoo of all places.

A blonde gets on a plane going to California and sits in !st class, the flight attendant tells her she has to move to coach, she responds: I'm pretty, I'm blonde, and I'm going to California.
The flight attendant tells the pilot, and the pilot goes to the blonde and tells her she has to move. The blonde says; I'm pretty, I'm blonde, and I'm going to California.
The co-pilot hearing the commotion ask what's the problem, so the pilot tells him.
The co-pilot says he speaks blonde because he's married to one, so he goes to her and whispers into her ear and she promptly gets up and moves to coach.
The pilot and attendant are amazed and ask the co-pilot what he whispered in her ear.
He said; I told her 1st class wasn't going to California