While I don't know anything about Alaska, Delta & TWA's airfreighters, I can tell you a little about American. AA had 8 707-323CFs & 6 747-123Fs over the years, altho not at the same time. AA got out of the pure airfreighter business when the bellies of the passenger aircrafts could carry almost as much freight, particularly the DC-10s & A300s...and still make money at it. American retired the 707s because they were getting old & required more maintenance...the 747s because of the fuel cost & again the belly roles of the passenger aircrafts. N7555A, N7556A, N7557A, N7558A, N7559A, N7560A, N7561A & N8404 were the 707-323CFs. N9661, N9671, N9672, N9673, N9675 & N9676 were the 747-123Fs. All were former passengers ships before being converted. Hope this helps. Regards.
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