Miami-Opa Locka Executive Airport is in Miami-Dade County, Florida 11 miles north of downtown Miami. Part of the airport is in the city limits of Opa-locka. The National Plan of Integrated Airport Systems for 2011–2015 called it a general aviation reliever airport.The FAA-contract control tower is manned from 7:00 AM to 11:00 PM. The airport has four fixed-base operators. It is owned by Miami-Dade County and operated by the Miami-Dade Aviation Department.The sole remaining military activity at the airport is Coast Guard Air Station Miami, operating from federal property not deeded to the county. It hosts EADS HC-144 Ocean Sentry turboprops; and MH-65 Dolphin helicopters for coastal patrol, deployment aboard medium endurance and high endurance coast guard cutters, and air-sea rescue. Much of CGAS Miami's facilities were built during World War II as part of Naval Air Station Miami.DayJet provided on-demand jet air charter services to 44 airports in 5 states; it filed for Chapter 7 bankruptcy liquidation in 2008.The airport is served by several cargo and charter airlines that use the U. S. customs facility. Maintenance and modification of airliners up to Boeing 747 size is carried out by several aviation firms.