It's fairly realistic excuse that civilian\hostile craft would be lacking the black market modifications for use by ubers and to not be tracked easily by authorities and\or former owners, so salvaging for parts is the best that can be done.
But the complaints about this are, i think, indicative of a different problem - early game craft capacities are very limited, most of them being a sidegrade from the starting airbus and its 6 capacity. Blowfish and Pigeon are a bit better but very slow, which is particularly bad in the period where getting in time to landings is important because you can't do interceptions due to lack of craft weapons (red codex gets screwed exceptionally hard with this because the craft weapon it gives comes without a source of ammo, so it's useless until you can buy or make spike rockets yourself). Skyranger and Pachyderm are almost the answer, but Skyranger is also pretty slow, Pachyderm is expensive, and around the time you get access to them you probably be getting access to the codex gated craft that are undisputable upgrades over the airbus, and competitive with Pachyderm while 50-75% cheaper.
That is the reason for why there is demand for a early game black market craft or few based on the bigger cousins of the starting Airbus. Unarmed, fairly fast, with 8+ spots and few aux capacity, even if a bit range limited, the speed sensitive landing missions are in base radar range by nature.
