McDonnell Douglas MD-12

The McDonnell Douglas MD-12 was an aircraft design study undertaken by the McDonnell Douglas company in the 1990s for a "superjumbo" aircraft, first conceived as a larger trijet, then stretched to a 4-engine airliner. It was to be similar in size to the Boeing 747, but with more passenger capacity. However, the MD-12 received no orders and was canceled. McDonnell Douglas then studied larger MD-11 derivatives named MD-XX without proceeding.