MarkXS

I'm not sure if you can book CO on delta.com anymore. I haven't seen any CO flights appear in award searches for a while now.

nwa.com still shows some CO award options, but every single one I've seen only has PerkPass availability even when CO themselves have saver availability on the same flights. It looks like Delta mgmt has decided to "mark up the price" on CO availability. Interestingly, CO has not retaliated - I just booked a mixed DL/NW flight for mid-October using my CO miles at saver levels no problem.

CO remains in SkyTeam through 24 Oct. As long as they are in SkyTeam, any SkyTeam FF program can book award tickets on them, and said tickets are good for 1 year from issuance. However that doesn't mean that said airlines' websites will offer them online.

I'd also be wary of booking with DL/NW miles for travel on CO after 10/24/2009. Though the tickets will be valid, DL will not be able (or at least not willing) to make any changes on them after that date. So for CO schedule changes, irrops, etc., you only have CO to work with. If you don't have CO status, they probably aren't going to put you at the top of their list for fixing your flight. Also unless you have CO, UA or some other *A status, your DL/ST status will be meaningless - thus any priority boarding, preferred seating, baggage allowances will be gone.

I've been doing the converse with my CO-miles awards for travel on DL/NW after 10/24. As a CO Plat with unlimited free changes/redeposits (sorry!) I've been replacing DL/NW flights with CO metal when CO has opened up availabilty. Which has been decent lately. What I can't find on CO, I'll try changing to UA or US post 10/27. Though I have status on DL, so don't have to worry about bag fees etc., I don't want to get caught up in IRROPS finger-pointing.