Can you make one of the planes be a cargo jet and a Airport that can be used as a train station so you can use planes to be used for upgrades to trains. That would be so cool, and something I dont get why the dev's haven't thought of yet.

I'm not sure of how to accomplish that, but it sounds like a good idea. I'll put it on a back-burner until I can figure out how.

Maybe make poles like that planes use to see at night and use it as a invisible train rail you wont be able to place items on it but because the planes you made go thought everything you can make it a lot easier to use then a train, maybe you can use the code for trains, but just make a special plane that can only go on said track? jumbo jet? Just throwing ideas around. I might look into this to see if i can help.

This idea is two years old, now, and somehow has died out.
When I read "cargo plane" I originally thought, the airport and automated routes would be a given, was a bit disappointed then to see, that this is only a player gimmick.
Since this game is all about automation, I think the airport really HAS to be done for this to be a useful addition. I like the planes but their use is limited.

So in case it still is unclear how to implement this idea, I'd like to try to dive into the SDK and help figure it out.

You're welcome to give it a shot and submit a pull request on the github, or release it standalone like some of the plugins I've seen here. I've got little time/interest in Factorio these days, so I'm not actively developing new features at least until 1.0/0.18 comes out.

@ stitch3210
Try https://mods.factorio.com/mod/AircraftRealism and https://mods.factorio.com/mod/aai-programmable-vehicles