http://www.courant.com/business/cus...eports-airline-miles-20110514,0,6845361.story Collecting frequent-flyer miles is easy because many credit cards offer air miles as rewards for all types of purchases. But spending those accumulated miles on travel is more difficult, according to Consumer Reports Money Adviser. Because airlines have a limited number of seats allocated to rewards use, it's not easy to book a dream vacation paid for by points. Instead, frequent-flyer programs are trying to get you to spend your miles on other things, such as merchandise, gift cards for a variety of retailers, and even tickets to sports and cultural events. Late last year, American Airlines added the option for miles holders to redeem their miles, or a combination of miles and cash, for hotel stays and car rentals. Delta and United/Continental frequent flyers already had that option. Both Delta and Continental even have websites where you can use your miles in an auction to bid for tickets to concerts at Carnegie Hall, footballs signed by NFL players and rodeos.