Phoenix is a major source for flights to Las Vegas. Here are some details:
Shuttles to Sin City
There are more daily departures from Phoenix to Las Vegas than to any other city. The route has the second most passengers of any out of Phoenix.
A look at the flights operated by the two major players:
• Southwest. 17 flights, goes to 16 in November as the airline tweaks its schedule.
• US Airways. 13 flights, goes to nine in October as part of seasonal schedule changes and the closure of the airline’s red-eye flight operation out of Las Vegas.
from: azcentral.com