Ask Randy: A reason to keep your NWA miles separate

— -- These are tumultuous times for frequent fliers, as struggling airlines continue to add new fees and restrictions to their loyalty programs. So we've invited frequent-flier expert Randy Petersen to take your queries and offer advice on how to make the most of your miles. Here are some recent queries; join him in his ongoing forum to post one of your own or help answer a question from a fellow reader.

Mike32: Randy, is there any benefit to not merging [Delta and Northwest] accounts now? And, when do you see CO flights not being eligible for NW / DL loyalty programs? Will one still be able to "top off" their points with AMEX Membership reward points? I appreciate the information on the lifetime mileage merger.

Randy Petersen:Thanks for the question. The reason for not merging is predicated on still wanting to participate and enjoy the promotions that NWA is offering right now. As you may be aware, SkyMiles and WorldPerks do not currently share the same partners or bonus offers, meaning that if you were to merge into a SkyMiles account right now, you may be losing out on some of the new WorldPerks offers and specific partners. I have elected to keep my WorldPerks program separate and active rather than merging into my SkyMiles account and adopting that as my only program of choice right now. I'm not in that much a hurry to see my combined mileage total — I can pretty much figure that out myself though it will make me a mileage millionaire!

As for CO flights. The last day that CO flights will count toward partnership miles into either a Delta or Northwest frequent flyer account is Oct. 24, 2009.

As for AmEx? There will be no changes since Continental continues with Membership Rewards after leaving this partnership and of course Delta continues as a partner. The good news is that now Northwest WorldPerks members (well, former ones anyway!) will be able to transfer Membership Rewards points into their new Delta SkyMiles account, whereas in the past they could not do that when it was truly Northwest WorldPerks.