A late night incident involving presidential candidate Barack Obama's plane has set off a National Transportation Safety Board investigation. The senator's aircraft clipped the wing of another plane at Midway Airport. No one was injured in the incident. Obama and his entourage were on their way back from campaigning in Nevada. The National Transportation Safety Board will look into this, but it is a relatively minor incident as far as airplane accidents go. The plane is parked now. Not going anywhere anytime soon. On board at 2:30 Saturday morning: Senator Barack Obama, three staffers, secret service and flight crew. The...