by Joseph Kenny | 07/1/09

For members of Northwest's WorldPerks program, the current merger of Delta-Northwest has become a matter of staying informed of the consolidation of the two airlines' mileage programs so they're assured that their Northwest miles will end up in a Delta SkyMiles account.

Northwest customers who are willing to participate in the program that survives the merger, Delta SkyMiles, will also have to face the decision about what credit card they will use for future mileage earnings.

The credit card that will be directly affiliated with the current SkyMiles card, is one issued by American Express. Consequently, the current WorldPerks card from Visa, offered by Northwest is being eliminated and then replaced by Visa's FlexPerks card. This phase out is set to begin between June and July 17, 2009, according to Northwest's website.

While this transition is ongoing, the WorldPerks cardholders will be issued new FlexPerks cards that they can choose to activate or not.

At the same time, American Express will be offering their SkyMiles card, along with various incentives meant to entice new customers. Thus, cardholders will have to decide between American Express and Visa.

On the one hand, you have the American Express SkyMiles card, which is an airline-affiliated card, very much like the credit cards affiliated with other major airline programs. Then there is the FlexPerks card, by Visa and U.S. Bank, which is a bank-issued credit card that comes with a travel rewards feature. This makes it similar to other cards like the Citibank PremierPass or Bank of America Elite Rewards cards.

One must compare and contrast the different styles of credit cards to see which one will be the best option.

Again, the FlexPerks card is like most other bank-backed cards meaning it earns points on dollars charged to the card for purchases. After a while, you can redeem points for free airline fare. Yet, it does have one good advantage and one disadvantage over airline-affiliated cards like the SkyMiles card.

With a FlexPerks card, tickets awarded will not be subject to blackout dates and capacity controls that can hinder consumers trying to redeem airline miles for free seats. The cards purchase tickets for users at the time they redeem their points. Unfortunately, FlexPerks points cannot be used with mileage earned in the SkyMiles program.

If miles are earned mostly with credit card purchases, then the FlexPerks card is the better option. On the other hand, if miles are earned through flying, hotel stays, and auto rentals, then airline-based credit cards like the SkyMiles card is better.

The choice of card will entirely depend on personal preferences and, perhaps, previous experiences using the WorldPerks credit card or other airline-affiliated credit cards.