Heathrow ATC (for the ZX Spectrum) was one that I played extensively back in the day: https://spectrumcomputing.co.uk/entry/10530 I wonder if there are earlier examples of popular ATC games? They're simpler than flight simulators so you'd think there would be more of them.

Edit: playable version - https://archive.org/details/zx_Heathrow_International_Air_Tr...