Hello,
I'm using the data files of your program in a computer science project with students and I've noticed two small errors in the routes.dat file:
Line 22166 is empty
Line 28216 is a route from SFO to SFO
If you're curious, I make them create the graph of all airports and routes and then find the shortest path (in distance) between two airports that can be realised by flying actual commercial routes.
Thanks a lot for your work on this files !