A boy is walking down the terminal with his mom when he sees a Northwest 747 parked next to a Delta 777. He ask his mom, "Why is that Northwest plane pregnant and that Delta one not." The mom replies, "I don't know son you need to ask a pilot that." A few moments later a confident and handsome Delta pilot walks by and the kid asks, "Why is the Northwest plane pregnant and the Delta one not?" The Delta pilot replies, "Well son, because at Delta we pull out on time!"