Originally Posted by
CPH-Flyer
They need routes that they can go out and back in less than 24 hours, so they only need one frame per rotation. I did not study the distances, but DEN is out for sure, and I would guess LAS and PHX as well PDX is already served by Delta and DEN by United so not quite unserved markets.
24 hour turn over but there's also maintenance work that they need to perform on the planes. Can't just keep flying 24/7/365.