FINALLY!
First off, my apologies to those who have been expecting this for a month or more; as mentioned in my prior post, my work schedule didn't make it any easier to carve out time to do the research, and nailing down the wording took far longer than I thought it would.
That said, here we go: Inspired by jlemon's "westbound round-the-world Southern Hemisphere odyssey" that entertained us recently, I came up with another 1983 trek for y'all to dissect ... this is a 14-segment summer jaunt from the U.S. to Europe and return; as usual, the task is to identify -- in sequence, of course -- the cities, airlines, and aircraft.
ON THE FIRST 12 FLIGHTS you'll arrive at one of several airports serving a major city or metropolitan area, but you'll depart from a different one.
>> You will NOT transit the same city or metropolitan area twice.
>> Proceeding west to east, the first five destinations are in the Continental U.S.
>> You will spend two nights at all U.S. destinations EXCEPT the third, where you will spend three nights.
>> From south to north, the next three destinations are in Europe.
>> You will spend one night at each European destination.
>> On return to North America there are four stops north to south.
>> You will spend two nights at each destination.
THE PENULTIMATE LEG returns you to a metropolitan area you have already visited, but via yet a different airport; you then depart from this same airport a few hours later and return to the airport where you began the journey.
The fine print:
IN ALL CASES the flight is on a different airline.
IN ALL CASES the flight is on a different model of aircraft -- e.g., 757-200 and 757-300 -- although three basic types -- e.g., 757 -- appear more than once.
IN ALL CASES -- except for one Fifth Freedom flight -- international flights are operated by an airline of the destination country.
TWO FLIGHTS only operate 1x/week.
The fine fine print:
>> There are several flights on each of two possible airlines for the second leg; all operate with the same model of aircraft.
>> There are two possible airlines for the fifth leg; each operates a different type of turboprop aircraft.
>> There are two possible airlines for the last leg within the Continental U.S; both operate the same model of aircraft.
>> Source data for U.S. flights is a Pocket Flight Guide, so there MAY be some additional answers that I didn't have the ability to consider.