They're a charter company out of Albuquerque, NM flying a metroliner. I was in Las Cruces tonight and asked the guy on the radio and he said the company's name was Southwest charter.
I'm a former "Taco" from the NMANG unit and that was a callsign they used when they flew vipers, not sure what they go by now that they're in the Herc's and helos.
Another common use of the "Taco" callsign is when I was in UPT if you were on any kind of checkride you'd go by "Taco XX"... Because the guy giving you a checkride would try to fail you and when you look at a taco from the side it makes a "U" when stands for unsatisfactory.... So, you know, it's an intimidation factor for military bros.
I tried to look that company up online and haven't found a website or anything so if you guys find anything so share. I'd be interested in finding out more about those guys flying around my neck of the woods from my hometown 😎