Note traffic figures only include domestic flights - so some of US & Mesa's Mexican flying boardings wont be included in the counts.
I'm a bit surprised AA is higer than UA, considering UA serves more destinations out of PHX than AA. Do these counts consider UA and CO together or separately? If UA and CO are counted seperately, then I can see why they are not in the top 5.
The Pink Delta 767-400ER - The most beautiful aircraft in the sky