In 2010, Airbus announced the A320neo project, intending to extend the life of the classic A320 series to the 2030s through new engines and aerodynamic improvements. The project is expected to deliver the first new aircraft in 2016, attracting widespread attention from airlines around the world. Boeing launched a successor project code-named Y1 in the same year, preparing to develop the next generation of the 737 series (later became the 737 MAX). This wave of competition for single-aisle aircraft swept the world.

However, McDonnell Douglas was in trouble. Although the MD-90 was still produced in small quantities, its model was old and its efficiency was backward, making it difficult to compete with the two major rivals. Faced with the double blow of market pressure and order loss, McDonnell Douglas decided to launch a project internally - the MD-100X project.
MD-100X is a McDonnell Douglas aircraft that replaces the v2500 of MD90 with CFM LEAP and adds the same winglets as MD11. The stargazing window is removed. McDonnell Douglas plans to launch it in 2017 and name it MD100X.

MD-100X features:

Low fuel consumption (about 15–17% more fuel efficient than MD-90)

Familiar model and maintenance features (easy to operate)

Cost-effective update solution (cheaper than a new design)

Although the design of MD-100X still retains the old fuselage outline and tail-push layout, it has been modernized through engine and wing