Joke of the Week courtesy Todd Rutledge:
A mother and her very young son are flying Southwest Airlines home from Kansas City to Pittsburgh (the t is silent) when the boy asks "If big dogs have baby dogs, and big cats have baby cats, why don't big airplanes have baby airplanes?"
Mom can't think of an answer so she instructs her boy to toddle down the aisle and ask the flight attendant, which he does. She smiled despite being busy and said "did your Mom tell you to ask me?"
The boy replied she did. "Well then, go tell your Mama there are no baby airplanes because Southwest always pulls out on time. Have your Mom explain that to you."