If you’re an avid traveler and you’re not using a credit card to accrue reward points, you’re sorely missing out on up to 6 percent in discounts with an American Express Gold Rewards.

It’s been long-contended that American Express has the best cards for the premium traveler to carry. By amassing points within the American Express Membership Rewards program or the Starwood Preferred Guest program, you’ll get the advantage of points-to-miles transfer options with a plethora of airline mileage programs –meaning your odds of finding available seats on the flights increases significantly.

The Membership Reward cards has 18 transfer partners and lets you buy up to 500,000 miles a year at 2.5 cents with great transfer bonuses throughout the year. The Starwood Preferred Guest program has 41 transfer partners and offers a 25 percent transfer bonus “every day” and on “every airline,” often amounting to a free upgrade.

But, what happens when the merchant doesn’t accept American Express? First Class Flyer’s Matthew Bennett rounded up the two best backup cards for the savvy business traveler to carry: the Chase Ultimate Rewards card or the Citi ThankYou Rewards card.

The Citi ThankYou Rewards has ten airline partners: Air France, Cathay Pacific, Ethiad Airways, EVA Air, Garuda Indonesia, KLM, Malaysia Airlines, Qatar Airways, Singapore Airlines and Thai Airways. It allows you to buy up to 100,000 miles at 2.5 cents per mile.

The Chase Ultimate Rewards Card has six airline partners: British Airways, Korean, Southwest, Singapore, United and Virgin Atlantic. It eliminated the option to buy points last year, probably due to the surge of signees who took advantage of the bonuses and don’t reciprocate value. United is the best airline to trade in points for with this card, but die-hard United fans fare much better with Amex cards or one of United’s four MileagePlus cards. But, Chase Rewards does have ongoing bonus-mile deals at gas stations, office supply stores and other similar offers that come and go.

For a cheat sheet on multi-airline credit cards or for information on ticketing strategies for bringing down the price of an award flight, check out Matthew Bennett’s October issue of First Class Flyer.