Aircraft altitude is established by Federal law. Title 14, Code of Federal Regulations Section 91.119 which governs flight states: "Except when necessary for takeoff or landing, no person may operate an aircraft below the following altitude: Over any congested area of a city, town or settlement, or over any open air assembly of persons, an altitude of 1,000 feet above the highest obstacle within a horizontal radius of 2,000 feet of the aircraft."