You just reminded me that the OAG back in the 70s use to have a fold out map of the USA and every non-stop route was on there with the airlines two-letter code(s) next to it indicating who flew the route. This was before deregulation, so I guess it was easier to keep up the map.
With routes changing all the time, it would be more difficult to do now. But in my opinion...route maps are god! I have a old Delta and United route map from the 1960s (the fold out kind) and you could trace your route as you flew across the country. I guess we now have GPS. Tracking flights real time has it's merits.
I use to write to every airline in the world and just sit down with an atlas, find the cities the airline served and create my own route map by connecting the dots from the schedule. Good way to learn the system. I just did this for Eastern Airlines from my 1962 OAG just to see where EA
flew back then. Man, that was one airline!
Computers have a lot of information in them but it is sometimes hard to grasp the entire operation unless you do this.