One travel rewards credit card can be better than several credit cards from different airlines, especially when there is no opportunity to combine miles earned on different airline credit cards. A travel rewards credit card, like the Discover it Miles card, will allow you to earn fixed miles on all your ticket and everyday purchases. Earned miles can be redeemed with any airline without limitations, restrictions or blackout dates. So even if you plan in advance or on the last day, or fly with different carriers, you still will be able to redeem miles for a ticket. Travel rewards credit cards may not give you such benefits like priority boarding or free checked bag, but therefore, they are cheaper and often come without an annual fee.