After doing some digging in the game files I found something interesting! This may be old news and I am not up to date, or this may be new, and I found a way to mod. Either way, I managed to make painted things to go onto taxiways. Find the pictures and spoiler video here:
This topic is concerning the files at (On windows)
/C:/Program Files (x86)/Steam/steamapps/common/AirportCEO/AirportCEO_data/datafiles
look around in there, as I am focusing on one specific thing. If you go to (From where you were using the instructions earlier) to
Companies/default/airlines you can see the files which are what all the airlines are based on. In an airline folder, there is info and the logo picture! I edited this picture using paint to get A, B, C. I Used the arrow tool to create the arrow. These image files are the logos that you get in the game, so that’s how I could use them. You must have the contract signed to access the logo. This is how I made the markings that you see on the screenshots. I tried creating a folder in the airline’s folder but it did not appear on the contracts menu so there needs to be more than a file in that directory. There are also tons of .meta files that I can’t open.
Feel free to comment/contribute to this! I will attach the files for the pictures with the A/B/C/arrow. I also made a deicing sign