i have been flying for thanksgiving on CO or HP since 1996. 5 years while in college and 5 while working. i usually buy thanksgiving in july or august and xmas one month later.

your $500-$700 are not going to get any higher until just before the holidays, so, basically, they have no where to go but down for now.

do one of these few things....

1) buy now and then wait for them to drop and get a future travel cert minus the $100 change fee.

2) buy a refundable Y, H or A,D,Z,R ticket which, many times, arent much more than the current offerings. that way, you can refund when/if they drop, or simply rest assured you're flying up front for the holidays (one of the best time to actually be up front).

3) just wait. price out the trip a couple times a month. dont go past august. use orbitz or travelocity to gauge what the other airlines are doing in comparison to CO. itll give you an idea on where the market is at the time.

some years it works great. other times, i end up paying $500+ to get to phx and back. that's when option two seems to have been the best.