Besides the above-mentioned routing & aircraft factors, DL to GCM is only 30K per person, while all others are 35K.

Yes, there is a penalty for cancelling an award ticket: IIRC $50 each on DL, $100 on UA or US. DL even penalizes date changes once the ticket has been issued, while US & UA don't ^. On DL if your favorite date or flight is unavailable & U grab 2nd or 3rd best, be sure to waitlist the better choices, because if the waitlisted flight opens up, U can grab it for no fee!

Since U have the DL miles, go ahead & book tonight, but I would not expect GCM in June to be gobbled up so far in advance. So book 3 tickets to Hawaii in Summer 2007 for 2008, then relax if it takes U till Jan. 2008 or so to get those last miles for the 4th (your own, since only U have meaningful UA or US miles to add to.)


If worse comes to worst, money-buy the last ticket or change dates for no fee.
Please note that UA & US awards allow flying on any combination of those 2 airlines (+ other Star Alliance airlines if going international.) So build up both those accts. just in case U want to invite a 5th person to Hawaii on your same plane .