You say the time to get to LV takes 45mins if that is in, say a 737? then at 500mph that is a distance approx of 379m. Depending on acrft of course but an example do it in a C152 you could reckon on 6-7 hours round trip which is not practical?
Phoenix to Las Vegas is around 240 NM, really. That can be done with a standard single engine aircraft in a little more than two hours one way, possibly faster with a more capable aircraft.
The approximation using airline cruise speed neglects that for shorter distances, an airliner will use (relatively) more overhead for taxi, take-off, climb, etc.