this thread was locked, so here's some additional answers.
Is route traffic affected by other adjacent routes you've created?
-- I have found that it can be if you start connecting cities w/multiple flights (i.e., paris-ny, london-ny, rome-ny, moscow-ny)
How do I make Concorde flights proffitable? You can vastly increase fares with them, but they carry so few passengers and they're so costly to maintain that I haven't found the proper use for them.
--You don't. I have NEVER gotten this to be profitable - too expensive to purchase, maintain, and fares are automatically higher than a sub-sonic plane. If you have these (starting as london/paris on scenario 2), ditch these IMMEDIATELY!
Best planes to use?
--Scenario 1 is prettymuch DC-8 until aircraft in Scenario 2 pop up.
--Scenario 2 - DC-9 (small hops), A-330 (the $55,000 one) (medium hops), 747 (large hops). If you can keep to only three or four types of planes, it'll make changing routes FAR easier. I have found that the 727 is good, but it's obsoleted too early. The 737 is nice, but the DC-9 has farther range. 767 is the only other Boeing I like to use, due to its B fuel rank and long distances. Often times, I switch out a 747 for a 767 if the route's losing passengers.
DC-10, MD-11, L-1011 are "niche" oddities that try to fill too many roles - a wide-body with average fuel consumption that can go medium-long routes just isn't that good - you'll either want max passengers, max range, or max fuel efficiency.
Airbus's A-320 is a good alternative to the DC-9, but again range is a problem.
Stay away from the Russian aircraft unless you're Moscow - then stick with the IL-62 and enjoy the range advantage over the DC-8. I NEVER used any of the other aircraft, except perhaps the TU-154.
So in summation
- Most common plane is DC-9 or A-330.
- Next most common is 747.
- Next is 767.
Happy flying. Can't believe I remembered all this after not playing the game for over 5 years!