Yes, you can sit together on Delta Air Lines, but your ability to do so for free depends on the type of ticket you purchase. If you book a Main Cabin fare or higher (Comfort+, First Class, or Delta One), you can select your seats for free at the time of booking, allowing you to choose side-by-side seating for your group. However, if you purchase a Basic Economy (Main Basic) ticket, your seat is not assigned until after check-in or at the gate. In this case, Delta’s automated system tries to seat parties on the same reservation together, but it is not guaranteed, and you may be separated if the flight is nearly full. In 2026, Delta has improved its "Family Seating" algorithm to ensure that children under 13 are seated with at least one adult from their party at no extra cost, regardless of the fare type. If you are a group of adults on a Basic Economy ticket who must sit together, the best 2026 advice is to pay the small "Seat Selection" fee available in the app after booking or to upgrade to a standard Main Cabin fare to secure your spots in advance.