Aerobatic flight.
CFR · 2024-01-01 · US · Title 14
No person may operate an aircraft in aerobatic flight— (a) Over any congested area of a city, town, or settlement; (b) Over an open air assembly of persons; (c) Within the lateral boundaries of the surface areas of Class B, Class C, Class D, or Class E airspace designated for an airport; (d) Within 4 nautical miles of the center line of any Federal airway; (e) Below an altitude of 1,500 feet above the surface; or (f) When flight visibility is less than 3 statute miles.
official document · source cfr-2024 · id 14:§ 91.303