Lorair is a charter airline based in Arizona (I think). Their aircraft (737-200) are currently operating for a charter airline out of Managua in Nicaragua called Caig Air (or something similar to that). I am sure it was Lorair which operated the 737-200s for the now defunct Tahoe Air.
Also, Nations Air is still operating. I was only talking to one of their managers last week. Can find out further details for you if you like. What exactly do ya want to know?