Carry-on rules for domestic economy-class travel differ from one airline to another, as shown in the table.

Airline........................................ Size (linear inches)

Alaska..................................................... 51

American................................................ 45

Delta....................................................... 45

Southwest.............................................. 50

United......................................................45

USAirways.............................................. 45

To determine the number of linear inches for a carry-on, add the length, width, and height of the bag.

(a) One Samsonite rolling bag measures 9 in. by 12 in. by 21 in. Are there any airlines that would not allow it as a carry-on?

(b) A Lark wheeled bag measures 10 in. by 14 in. by 22 in. On which airlines does it qualify as a carry-on?