[mysterydip]

I found this book by Chris Lampton to be very helpful for my own 3D DOS pursuits: https://archive.org/details/build-your-own-flight-sim-in-c-d...

There's also various article series in the flipcode archives: https://flipcode.com/archives/articles.shtml

[myth_drannon]

Also first edition of this book from 1993: https://archive.org/details/flightsoffantasy00lamp

You can also find the source code on archive.org if you don't feel like typing everything.