under seat airline luggage
Just because an item can fit under the seat of an airline seat, this does not mean that it meets the airline's size requirement. Some airlines give exact size specifications while others only require that the luggage's sum total of length, width and height is not larger than a given linear length. The space under the seats in Delta 757-300 model plane is 20 inches wide, 17 inches deep and about 11 inches tall. Delta mandates that baggage brought into a plane's cabin cannot be more than 22 x 14 x 9 or 45 linear inches.