As a first principal I always had Morrow Project do its shopping in cancelled military procurement. During the period that the Project was active 1950 to TEOTWAWKI (1989 in original canon) there were a lot of projects that produced some exciting equipment that for one reason or another never entered full production. In my Project (YMMV) I had them scoop up a number of these sets of hardware, convert them to fusion/electric drive and otherwise Morrowize them.
For aircraft I chose Vertical Take off systems only but that gives a really nice choice of platforms. These are some I chose
XC-142 Tilt wing cargo aircraft
https://en.wikipedia.org/wiki/LTV_XC-142 5 build
CL-88 Tilt Wing light aircraft
https://en.wikipedia.org/wiki/Canadair_CL-84 4 built
XV-15 Tiltrotor light aircraft
https://en.wikipedia.org/wiki/Bell_XV-15 2 built
AH-56A Cheyenne Compound helicopter Gunship 12 built
These I positioned as follows
XC-142s at Prime base replacing or supplementing the C-130s in canon
XV-15 at Prime Base
Four "aviation bases" each with either four Cheyennes or the four CL-84s. These would be scattered about but within range of supporting each other and Prime Base and possibly the Back Up Base as well