Rewards loyalty programs offer incentives to customers for using certain credit cards. Miles cards are very popular and in some cases they let customers accrue frequent flyer miles that they can use to buy plane tickets. Other miles rewards programs offer miles as points that can be put toward travel purchases. Miles rewards cards may be issued by airlines, as co-branded airline cards, or by credit card networks that let you use the miles to make travel purchases. Miles rewards can also usually be used for travel upgrades and perks like free baggage checking, VIP lounge access, and more.