This morning I was flying on NW DC-9-30 N8929E STL-DTW, which was built in 1967. Would the DC-9 fall into the 1st or second generation jet category?
Some would say that the 1st generation jets are the B707, DC-8, Caravelle, Comet, and CV880 as they brought us the first jet travel. With the exception of the Caravelle and CV880 they were long range planes, at least for the time. They did not push all the piston powered passenger planes out of the sky though. Planes like the Connie and DC-6 went on to fly less prestigious routes with major carries for several more years. Planes like the DC-9 and 727 came along in the 1960s and pushed the piston airliners out of the secandary routes. I would say that any jet plane that pushed out piston on mainline travel for a major carrier is a 1st generation jet.
I get this theory from my other hobby of railroading. It is commonly thought in North America that 1st generation diesels, like the EMD GP-7 are the diesels that replaced steam engines and 2nd generation diesels, such as the EMD SD-40 are the models that replaced the 1st generation. Third generation is the models that replaced those, such as EMD SD-70s. Of course there are still old locomotives all over the place on secondary railroads and on large railroad branches, but the last steam was displaced on mainline class one railroads in 1962 (on the Colorado & Southern). The transition from steam locomotive to diesel was reasonbly fast, with the first all diesel class one being GM&O in 1949 to Colorado & Southern (CB&Q), in 1962 being the last. The piston engine airlines left the major carriers just as fast.
DC-9s certianly didn't replace 707s or DC-8s, it was planes like the A300 or 757 that did that, that being the second generation. DC-9s were replaced by newer 737s, MD-80s and A319s. DC-9s were built all the way to 1982, the last being a DC-9-30. That is if you don't count and MD-80s as DC-9s. Certianly by 1982 the first generation of jetliners had passed, but where do we draw the line? The last passenger 707 was built in 1978 and that certianly isn't 1st generation jet era either.
What do you think? How are the generations of jetliners classified?