In the early 1970s, several airlines approached McDonnell Douglas for noise reduction modifications to the DC-8 but nothing was done. Third parties had developed aftermarket hushkits but there was no real move to keep the DC-8 in service. Finally, in 1975, General Electric began discussions with major airlines to fit the new and vastly quieter Franco-American CFM56 engine to both DC-8s and 707s. MDC remained reluctant but eventually came on board in the late 1970s and helped develop the Series 70.