As a PLT and based in PHX upgrades are a dream, however, there are some sweet spots, Friday evening, Sat and Sunday mornings PHX-SAN have been upgraded about 80%. I might have found a unicorn PHX-SAF (Santa Fe NM) we have taken this trip 3 times, first time out no upgrade (Mondy flight) return was Sat both us upgraded) We have left Wed and returned Sat (upgraded both times) This is on CRJ-700 only one flight a day, leaves in the late afternoon and returns early evening. With PLT I like that I can choose MCE seats at booking which makes for a nicer ride.