I've experienced clapping a few times, but a few stand out. In high school I flew with my youth group to Israel. Lots of clapping when we landed in Tel Aviv.
And on the return flight lots of clapping to be back in America.
And a few days after Sept. 11th, I flew the first AA flight from BOS-LAX. As soon as we touched down at LAX, the entire plane erupted into cheers and non-stop clapping all the way to the gate!!!