These portals, often run under contract by a third - party, run regular promotions that let you earn a certain number of miles or points for every dollar you spend. (travelcodex.com)
That amount is multiplied by the number of miles or points earned per dollar spent on everyday purchases to account for cards that earn more than one mile per dollar spent. (rewardexpert.com)
The quickest way to do that is to earn miles or points with travel rewards credit cards and redeem them for award flights. (rewardexpert.com)