3D buildings for airports

explor8flights

I have noticed many pretty airports, with nice highways and lights, but I still feel that buildings could use better quality/accurate meshes, so my question is that, it is possible to import more detailed meshes/buildings for the scenes?

some examples:

https://free3d.com/3d-models/building

I understand that it needs format .ac , and not .obj or .dae, am I right?

thank you in advance

OrbitalMartian

https://forum.fguk.me/discussion/439/3d-buildings-for-airports

It has to be .ac for FG, correct and the license for the model must be GPL.