how much room is under the seat on united flights
AirTran specifies a 55-inch carry-on; Alaska Airlines regulates 24 inches by 17 inches by 10 inches; American Airlines specifies 45 inches; America West and Continental are 51 inches; British Airways regulates 22 inches by 16 inches by 8 inches; and Spirit is 22 inches by 14 inches by 10 inches. References.