Delta Air Lines assigns seats in the Main Cabin based on the specific "Experience" you purchased: Basic, Classic, or Extra. If you book a "Delta Main Basic" (formerly Basic Economy) ticket, your seat is not assigned until after you check in—usually within 24 hours of departure—or even at the boarding gate itself. You have no control over your location and are often assigned middle seats or separated from travel companions. For "Delta Main Classic" and "Extra" fares, you can choose your seat for free at the time of booking from the available standard inventory. Delta’s automated system also holds a certain number of "Preferred" seats (aisles and exits near the front) for its Medallion elite members. If a flight is nearly full, the gate agents use a "Priority List" to fill remaining gaps, often moving families with children together as a priority under new 2024/2025 consumer protection guidelines. If your boarding pass says "Seat Assigned at Gate," it simply means the system is waiting to see which premium passengers get upgraded before releasing the final Main Cabin inventory to you.