On almost all commercial aircraft with a standard 3-3 or 3-3-3 seating configuration, Seat C is an aisle seat. Seats are typically lettered from left to right when facing the front of the plane. In a standard narrow-body jet (like a Boeing 737 or Airbus A320), Seat A is at the window on the left, B is the middle, and C is the aisle on the left side of the cabin. Seat D would then be the aisle seat across the way on the right side, followed by E (middle) and F (window). In 2026, some low-cost carriers or smaller regional jets may have different configurations (like 2-2), but the "C as an aisle" rule is remarkably consistent across global airlines like Delta, Lufthansa, and IndiGo. Knowing this helps you quickly identify your location during boarding; if you see "C" on your boarding pass, you can expect the convenience of easy access to the lavatory and overhead bins without having to climb over your neighbors.