In another thread a week or so ago, it came up that back when dinosaurs roamed the earth, fares changed so infrequently airlines could publish them in their timetables with little fear of being inaccurate. Rummaging around this afternoon I ran across where I had some old TWA timetables, and one I'd kept did indeed have the fares for every domestic city pair listed along with the flight times (international fares were listed separately across two pages of rules, and two pages of fares and fare add-ons).
The last TWA timetable I have with fares was effective June 7, 1979. The next most recent timetable I saved was effective October 1, 1980, and the fare information had vanished. The 1980 timetable had also shrunk in size from 75 pages to 23 pages due to a newer condensed style of listing flight times.
Sample fares from TWA's July 1979 timetable (all listed as round trip
to compare with the excursion fares, even though the First and Coach fares--both without restrictions--were published as one-way):
San Francisco - New York round-trip:
$588.00 First Class (F)
$490.00 Coach (Y)
$490.00 First Class Night (FN)
$392.00 Night Coach (YN)
$343.00 Super Saver Peak - Fridays, Saturdays, Sundays (YWE6)
$294.00 Super Saver Off-Peak - Mondays thru Thursdays (YXE6)
$294.00 Super Saver Night Coach Peak - Fridays, Saturdays, Sundays (YNWE6)
$245.00 Super Saver Night Coach Off-Peak - Mondays thru Thursdays (YNXE6)
Chicago - Denver round-trip:
$262.00 First Class (F)
$218.00 Coach (Y)
$153.00 Super Saver Peak - Fridays, Saturdays, Sundays (YWE6)
$131.00 Super Saver Off-Peak - Mondays thru Thursdays (YXE6)
$ 98.00 Excursion (K)
From some of the footnotes, it appears that even though routes had become deregulated in 1978, fares were still regulated for a while, since a few are listed as "Subject to CAB approval," which could explain why fares were still rather stable and could continue to be published at that point in time.