Originally Posted by
WHBM
Some discussion points for a wet and cold (well, it is here in London) weekend.
There have been a number of aircraft types over time which have been pretty much directly competitive, and airlines make the choice to have one or the other.
But which US airlines had BOTH ......
a) Tristar and DC-10.
b) 707 and DC-8.
c) 737 classic and DC-9.
.
Others have answered, here are more...
L-1011 Tristar and DC-10: United, getting the Tristars from Pan Am
707 and DC-8: Pan Am, ordered both new
737-200 and DC-9: Delta, technically Southwest (had DC-9-82 operated by Muse Air, which Southwest acquired), Alaska
It's possible that the original question seeks to exclude the MD-80, which was certificated as the DC-9-80 series, in which case, Delta is an answer.