Every time I stay in Las Vegas, I always take the Executive Las Vegas shuttle from my hotel to the airport. They're extremely reliable and very affordable ($7 a person). During my last trip, I took the shuttle from the Flamingo to McCarran Airport. An Executive Las Vegas shuttle was waiting outside of baggage claim, and Brian was extremely courteous and friendly. He helped us both with our bags and got us to the airport quickly and safely. I find them much more reliable than cabs.