Determining fitness to fly is a difficult task for physicians, especially for those caring for children with respiratory disorders, as the available information for guidance is scarce. This case describes the use of a flight simulation in a decompression chamber in order to assess fitness to fly in an 18-mo-old infant with congenital lobar emphysema (CLE). The case discussion focuses on the need for an understanding of flight physiology in order for physicians to determine the most appropriate method to assess fitness to fly in children with medical concerns.