Now, this is a real joke.

A jet plane, just before take off, abruptly stopped on the tarmac, turned around
and returned to the gate. After an hour-long wait, it finally took off.

A concerned passenger asked the flight attendant, "What was the problem?"

"The pilot was bothered by a noise he heard in the engine,"
explained the flight attendant.

"Oh, so, there won't be any noise now?-the passenger.

You see, it took us a while, not to fix the noise but to find a new pilot."

Source:Amusing facts.