Seat sizes on Airbus A320 aircraft vary by individual airline and passenger class. Airbus offers the A320 with economy class seats that are 17 to 18 inches wide.
Websites such as SeatGuru and SeatExpert allow users to view seat maps for many major airlines. These sites provide details about seat width and leg room for each aircraft type. Economy seats in Delta's A320 planes are 17.2 inches wide, while economy seats on United A320s are 17.8 inches wide.
Some airlines offer premium economy seats that are less expensive than first or business class. These seats are usually the same size as economy class seats, but offer extra leg room.