Virgin America will also be the only airline offering a red-eye from Las Vegas to Dallas, allowing Dallas-originating travelers to maximize their time taking advantage of everything Vegas has to offer before returning home.
Based on some random searches - AA has a LAS-DFW flight that departs at 12:59am and NK has a flight that departs between 1:20am - 1:50am. So, I am guessing by "only airline offering a red-eye" they mean compared to WN at DAL?