The flight school is at San Antonio International. Does anyone know if the tower there closes at night?
A major airport like San Antonio would not close, but there are numerous smaller airports in the south Texas region.
In the 1980's my firm was flight testing a UAV for possible sale to the US Army, we flew "captive carry" flights out of Alice Texas and our flights were basic survellence missions that an Unmanned Air Vehicle would fly. We flew at night with IR and in day with normal TV. One day when we tossed a roll of test data out the window to our flight base near the Mexican border, we were met with several members of the DEA who had been watching our flights with interest. They demanded to see the roll of test paper then they intercepted and inspected the plane when it landed in Alice. You can guess what they thought our operation was intended to do. The point is that lots of eyes watch these airports and landing strips, but in the desert, a landing strip can be made quickly and simply and would not be well known until people were detected using it.