Delta SkyMiles is a frequent flyer program offered by Delta Air Lines. Members earn miles for flights taken with Delta and its partner airlines, which can be redeemed for free flights, upgrades, and other travel-related benefits. The program also allows members to earn miles through hotel stays, car rentals, and everyday purchases. Members can achieve different status levels, such as Silver, Gold, Platinum, and Diamond, which provide additional perks like priority boarding and bonus miles. Delta SkyMiles has no expiration date for miles, making it easier for travelers to accumulate and use their rewards over time.