Here's my current SecondaryAirports class within class sws_twinlakes - it adds the Mountain Base airport. Takeoff is in the direction of bearing 90. Glidescope is a little steep to avoid hitting trees.

Taxiway is on the south edge of the strip. It works very well with vanilla Hangar structures placed at [10600, 21520] and [10560, 21520], leaving the other side of the road for support vehicles, repair/rearm/refuel, infantry camp, field HQ, etc.

AI planes should be spawned either just in front of those hangars or halfway inside to avoid issues.

class SecondaryAirports{
class Airstrip_1{
ilsPosition[] = {10382,21590};
ilsDirection[] = {-1,0.105,0};//Using steep angle to avoid striking trees on approach
ilsTaxiOff[] = {10826,21590,11270,21590,11277.5,21580,11280,21570,11277.5,21560,10955,21560,10630,21560};
ilsTaxiIn[] = {10600,21560,10560,21560,10480,21560,10400,21560,10384.5,21560,10382,21570,10384.5,21580,10392,21590};
drawTaxiway = 1;
};
};

Map image: https://drive.google.com/file/d/1UjAdEooR29qAQ4xsPb3iB74k7zWoMk53/view?usp=sharing

It was tested with all vanilla planes, and some CUP ones. Some CUP ones like the L-39ZA may have issues just because their flight model isn't great, and the margin for error on the AI glidescope isn't huge.

Nice. I didn't get notified of this for some reason. Will check it out...

Got the south airport done. Surprisingly easy to transform the mountain base airport using markers. There is still some grass clutter near the end of the runway and taxiway, but that's not really an issue.

Since the terrain is very flat, planes will fly very low right over the dirt road at the south end of the runway when landing. It's kinda cool to watch (since some real life airports are like this), but it might be a good idea to add some warning/stop signs or some other marker to signal to players not to park right behind the runway.

Class for the south airport config:

class Airstrip_2{
ilsPosition[] = {26955.861,3797.064};
ilsDirection[] = {0.4550787305,0.069756,-0.8904512053};
ilsTaxiOff[] = {26758.357,4183.524,26474.623,4739.283,26462.307,4741.409,26452.25,4739.088,26435.594,4727.756,26664.043,4280.189,26757.324,4097.648};
ilsTaxiIn[] = {26770.984,4070.933,26802.844,4008.603,26857.443,3901.747,26880.2,3857.229,26919.107,3781.093,26938.039,3787.963,26945.824,3794.741,26951.314,3805.971};
drawTaxiway = 1;
};

thanks for making these!