Book excerpt: This synthesis study is intended to inform airport operators, stakeholders, and policy makers about common use technology that enables an airport operator to take space that has previously been exclusive to a single airline and make it available for use by multiple airlines and their passengers. Common use is a fundamental shift in the philosophy of airport space utilization. It allows the airport operator to use existing space more efficiently, thus increasing the capacity of the airport without constructing new gates, concourses, terminals, or check-in counters. This synthesis was prepared to help airport operators, airlines, and other interested parties gain an understanding of the progressive path of implementing common use, noted as the common use continuum. It identifies advantages and disadvantages to airports and airlines, and touches on the effects of common use on the passenger. The information for the synthesis was gathered through a search of existing literature, results from surveys sent to airport operators and airlines, and through interviews conducted with airport operators and airlines.