Sierra Aviation Group, located in Ontario, Calif., provides a variety of specialized outsourced services for airports in Palm Springs, Calif., Ontario, Calif., and Orange County in California. Its services include skycaps, wheelchair attendants, I.D. checkers, baggage handlers, security screeners, lost baggage delivery, airport janitorial service and aircraft cleaning. It provides service at John Wayne Airport in Orange County, Palm Springs International Airport and Ontario International Airport.