In X-Plane, we design airfoils - like you do in real.
The flight model uses this as a base for it's calculations.
Cm, Cd and Cm at different AoA's, Re# etc.
You can use/create real ones (NACA or whatever) or invent your own.
The model will perform accordingly.
There is offcourse 1000's of other variables we enter as well.
Body's are offcourse modelled also.
So, you could say that unlike MSFS, XP has an athmosphere. ANYTHING you put in it will get affected by forces.
I'm sure that MSFS has an atmospheric model too; that's not a feature that you need to have calculated coefficients for. Our FFS sim models have an atmosphere, and we use lookup tables. It couldn't be otherwise.
And whether the aerodynamic data are in lookup tables is somewhat secondary - the key is what is the BASIS of the aerodynamic data. One could run the CFD-like routines in Xplane to generate lookup tables, and obtain the same degree of fidelity with either the lookup implementation or the "calculation" implementation.
For a "real" simulator we have no choice than to use lookups, because our models are ultimately based upon flight-matched data, not CFD or impirical predictions - we start with the latter, implemented in a tabular format for reasons of code execution and efficiency, then gradually the data are refined in the light of measured flight test responses.
To be frank, I'd be more trusting of sparse, but flight test derived, data, than I would be of wholly predicted data; there are too many times when the "predictions" guys say "but we didn't predict that" for me to be comfortable without some validation.