Regarding cmyden's "drive and fly" post -- we did this once last year (spent 5 days in Phoenix, bookended by overnight stays in Great Falls), and it worked out really well. We usually head down to Montana a few times a year just for shopping anyways (I'm amazed at how much you can save over Canadian prices -- enough to basically subsidize the trip including hotel and gas). So the cost was definitely in our favor (considering how cheap our flights were on Allegiant), plus the ability to bring stuff back in a car versus trying to cram it into a suitcase.
With two little ones that now (or will soon need) tickets of their own, I can definitely see us doing it again. Didn't know they started charging for carry-on's, but I guess that's just more incentive to pack light
