: Much of the game's logic, including airport configurations and flight characteristics (speed, attitude, etc.), is controlled through CSV (comma-separated values) files . These can be edited with basic tools like Notepad or Excel to modify how the game operates.
zip file, or are you interested in the configuration files? File: Tower.Simulator.3.zip ...
For a deep dive into the basics, you can refer to the official Start Guide - Basics for Tower! Simulator 3. : Much of the game's logic, including airport