The MD-90 was developed from the MD-80 series and is a 5-foot-longer (1.5 m), updated version of the MD-88 with a similar electronic flight instrument system (EFIS) (glass cockpit), and improved, and quieter IAE V2500 high-bypass turbofan engines.
The MD-90 program began in 1989, first flew in 1993, and entered commercial service in 1995.

Several other proposed variants never entered production.
One proposal was the MD-94X, which was fitted with unducted fan turbofan engines.
Previously, an MD-81 was used as a testbed for unducted fan engines, such as the General Electric GE36 and the Pratt & Whitney/Allison 578-DX.

The MD-95 was developed to replace early DC-9 models, which were approaching 30 years of age.
The project completely overhauled the original DC-9 into a modern airliner.
It is slightly longer than the DC-9-30 and is powered by new Rolls-Royce BR715 engines.
The MD-95 was renamed "Boeing 717" after the McDonnell–Douglas—Boeing merger in 1997.
The MD-90 was developed from the MD-80 series and is a 5-foot-longer (1.5 m), updated version of the MD-88 with a similar electronic flight instrument system (EFIS) (glass cockpit), and improved, and quieter IAE V2500 high-bypass turbofan engines. The MD-90 program began in 1989, first flew in 1993, and entered commercial service in 1995.
Several other proposed variants never entered production. One proposal was the MD-94X, which was fitted with unducted fan turbofan engines. Previously, an MD-81 was used as a testbed for unducted fan engines, such as the General Electric GE36 and the Pratt & Whitney/Allison 578-DX.
The MD-95 was developed to replace early DC-9 models, which were approaching 30 years of age. The project completely overhauled the original DC-9 into a modern airliner. It is slightly longer than the DC-9-30 and is powered by new Rolls-Royce BR715 engines. The MD-95 was renamed "Boeing 717" after the McDonnell–Douglas—Boeing merger in 1997.
McDonnell Douglas MD-80