In late 1991, McDonnell Douglas made a move to separate its civil and military divisions in a bid to raise the estimated $4 billion development costs needed to develop the MD-12X trijet.
Separating the costly military C-17 airlifter development, which had been a drain on the company's resources, from the profit-making production of the MD-80 and MD-11 airliners would make it easier to attract foreign investors for the MD-12X.
The design grew into the much larger MD-12 with four engines and two passenger decks extending the length of the fuselage.
 The length of the main MD-12 variants was 208 ft (63.4 m) with a wingspan of 213 ft (64.9 m).
 The fuselage was 24 ft 3 in (7.39 m) wide by 27 ft 11 in (8.51 m) high.

McDonnell Douglas unveiled its MD-12 design in April 1992.
The design was similar in concept to the Airbus A3XX and Boeing New Large Airplane, and it would have been larger than the Boeing 747 with which it would have directly competed.
 Douglas Aircraft had also studied a smaller double decker design in the 1960s.

The first flight of the MD-12 was to take place in late 1995, with delivery in 1997.
 Despite aggressive marketing and initial excitement, especially in the aviation press, no orders were placed for the aircraft.
MDC lacked the resources after Taiwan Aerospace left the project.
Some skeptics believed that MDC launched the project to lure Boeing into paying a higher price for the company.
A new double deck widebody has proved to be extremely expensive and complex to develop, even for the remaining aerospace giants Boeing and Airbus, although the massive Airbus A380, a similar concept to the MD-12, was later brought to fruition.
In late 1991, McDonnell Douglas made a move to separate its civil and military divisions in a bid to raise the estimated $4 billion development costs needed to develop the MD-12X trijet. Separating the costly military C-17 airlifter development, which had been a drain on the company's resources, from the profit-making production of the MD-80 and MD-11 airliners would make it easier to attract foreign investors for the MD-12X.
The design grew into the much larger MD-12 with four engines and two passenger decks extending the length of the fuselage.  The length of the main MD-12 variants was 208 ft (63.4 m) with a wingspan of 213 ft (64.9 m).  The fuselage was 24 ft 3 in (7.39 m) wide by 27 ft 11 in (8.51 m) high.
McDonnell Douglas unveiled its MD-12 design in April 1992. The design was similar in concept to the Airbus A3XX and Boeing New Large Airplane, and it would have been larger than the Boeing 747 with which it would have directly competed.  Douglas Aircraft had also studied a smaller double decker design in the 1960s.
The first flight of the MD-12 was to take place in late 1995, with delivery in 1997.  Despite aggressive marketing and initial excitement, especially in the aviation press, no orders were placed for the aircraft. MDC lacked the resources after Taiwan Aerospace left the project. Some skeptics believed that MDC launched the project to lure Boeing into paying a higher price for the company. A new double deck widebody has proved to be extremely expensive and complex to develop, even for the remaining aerospace giants Boeing and Airbus, although the massive Airbus A380, a similar concept to the MD-12, was later brought to fruition.
McDonnell Douglas MD-12