An airliner disappears without a trace over water, vanishing from radar without a Mayday or witness to its final fatal moments. As searchers continue to look for the Malaysia Airlines flight that failed to reach its destination last weekend with 239 on board, there's an eerily similar mystery that's much closer to home — the unsolved fate of Northwest Orient Airlines Flight 2501, which crashed into Lake Michigan in 1950. At the time, Northwest 2501 was the worst commercial aviation disaster in U.S. history with 58 people lost. Though debris and body parts were found, the wreckage is still somewhere...