Delta miles are easy to earn by flying, with co-branded credit cards, or by transferring Amex points. You can use Delta miles for flights on Delta or its partners, including Air France and KLM. The best deals are often through Delta's award sales, and your miles will never expire. Delta is currently the world's second-largest airline, and if you live in a hub city like Atlanta, New York, or Seattle, it may be your carrier of choice. Because Delta's route network is so ubiquitous inside the US and because Delta SkyMiles are (relatively) easy to get, there are many different options for redeeming your miles with Delta and its partners in the SkyTeam alliance — though not all of them offer the best value.