Does anyone remember a PC flight sim from the (mid?) 90s that supported dogfights over a null modem cable? Have been trying to remember its name for ages.
Strike Eagle 3 (the successor to version II) could do this. It supported null-modem as well as Ethernet/IP connectivity to do dogfights, campaigns etc.
Yes, the game you're thinking of is likely "Chuck Yeager's Air Combat," developed by Electronic Arts and released in 1991. It was one of the first flight simulation games to support multiplayer dogfights over a null modem cable. Players could connect two PCs directly via a null modem cable and engage in aerial combat against each other. The game was quite popular for its time and is fondly remembered by many flight simulation enthusiasts.
IIRC there was one which was multiplayer pre Internet. You called in to a BBS like server with banks of modems. (I think there were 20 players or something like that in a game.)