17. (1985) Per schedules available in the 1985 North American OAG I used to reference these questions, only two airlines still offered service to Toronto’s Lester Pearson International Airport with McDonnell-Douglas DC-8s – one with a standard DC-8 and the other with a stretch DC-8. Identify each airline, the DC-8 variant it served YYZ with and where each flight came into Toronto from.
I have to believe that the -50 was Aeromexico, probably a less-than-daily service from Acapulco/ACA; both Air Canada and CP Air had retired their Stretch 8s a couple years ago, as had Air Jamaica, so maybe this example at YYZ was a United turn from Chicago/ORD
AeroMexico is indeed one of the airlines. United would seem a very likely choice and yet - we're looking for a different DC-8 operator. Please, carry on!
27. (1990) Vermont sure is pretty in the fall, so when you’re informed that you’ll have to head out of town on business next Monday you’re not too happy about it. On a positive note, your destination is beautiful Savannah, GA and to make matters even better, there’s a single daily one-stop direct flight departing Burlington each evening. Book it, Danno! Identify the usual triumvirate – airline, enroute stop and equipment please.
A few years earlier I would have said this was a good candidate for a Presidential Airways BAe 146 operating via Washington Dulles/IAD; it wouldn't surprise me if United kept operating the route, although more likely with a 737-300
Well you're right about United and the aircraft was indeed a 737, but not the -300. That leaves... the -200.
United UA 1035 Burlington (BTV) 555p-732p S Washington (IAD) 805p-944p Savannah (SAV) 737-200 X6
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Apologies in advance, I just have to ask this...
From the rules: LH was doubtless a Series 30 aircraft; BA's ex-Laker fleet, and I think most if not all of AA's, were the Series 10 ... granted, with the exception of the centerline main gear, they were indistinguishable, but still ... 
Where I draw the line is where there are significant differences in aircraft size or shape. For example, a 727-200 is 20 feet longer than the -100, a DC-9-50 is longer than a -30 and has the forward canards, etc.
With the DC-10s, outwardly there is little difference. They are all the same size. Unless one is aware of the nacelles and is aware of the center landing gear, the average viewer likely be unable to differentiate between them. And of course the MD-10 has the glass cockpit.
The MD-11 is a whole nother beast.
So again, I draw there line where there are easily and visually discernable differences in size and/or shape (737NG tails are different from Classics, etc.)
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