Delta operates a variety of cabin classes on its aircraft, including economy, Premium Select, first class and Delta One seats. Like most airlines, Delta will allow you to select your seat when booking, though the cost to do so and any upcharges will vary depending on the flight you're taking.

On Delta Air Lines, you cannot sit wherever you want; you must sit in the specific seat assigned to you on your boarding pass. Delta operates on a reserved seating model, meaning every passenger is allocated a designated row and seat letter (e.g., 12A) prior to boarding. The ability to choose or change your seat depends heavily on your fare class. For example, "Basic Economy" passengers typically do not get to select a seat for free and are assigned one at check-in or at the gate. Those in Main Cabin, Delta Comfort+, or First Class can usually select their seats in advance through the Delta app or website. While you might see empty seats after the cabin doors close, you are not permitted to move to a higher class of service (like moving from Main Cabin to Comfort+) without paying an upgrade fee. If you wish to switch seats with another passenger in the same cabin, you should wait until after takeoff and ask politely, but the flight crew generally prefers that everyone remains in their assigned seats for weight and balance purposes and manifest accuracy during the flight.