Tamrac designates a product as carry-on compatible if it is within the dimensions of 22" wide x 14" deep x 9" high, which is the maximum carry-on size commonly used by most USA airlines.  Please note that even if baggage meets these size requirements, it is still possible that the airline will not allow it on board for a variety of reasons totally within their discretion.  Additionally, not all airlines have the same carry-on restrictions and travelers should check with their particular carriers prior to travel to verify the size restrictions.