• Maximum Altitude: 400 feet (120 meters) AGL is the standard limit, especially in Class G (uncontrolled) airspace.
• Structure Exception: When inspecting or photographing a tall structure, you may fly 400 feet above the structure's highest point, provided you stay within 400 feet horizontally of it.
• Controlled Airspace: In Class B, C, D, or E airspace, you must receive FAA authorization (via LAANC or DroneZone) and typically still abide by the 400-foot cap, or lower if dictated by the authorization.
• Terrain Factors: Pilots must be aware that flying over uneven terrain (cliffs, valleys) means the 400-foot rule applies to the ground directly beneath the drone, not the takeoff point.
• Exceptions & Waivers: Commercial operators (Part 107) can request waivers for operations above 400 feet if they can demonstrate a safe plan, such as for high-rise building inspections.
• International Variations: While 400 feet (120-122m) is common, some countries differ, such as Germany (100m) or Indonesia (150m). 

The ability to fly over people varies depending on the level of risk that a small UAS operation presents to people on the ground. Operations over people are permitted subject to the following requirements:

• Category 1 small unmanned aircraft are permitted to operate over people, provided the small unmanned aircraft:
  • Weigh 0.55 pounds or less, including everything that is on board or otherwise attached to the aircraft at the time of takeoff and throughout the duration of each operation.
  • Contain no exposed rotating parts that would cause lacerations.

In addition, for Category 1 operations, no remote pilot in command may operate a small unmanned aircraft in sustained flight over open-air assemblies unless the operation is compliant with Remote ID.

• Category 2 and Category 3 provide performance-based eligibility and operating requirements when conducting operations over people using unmanned aircraft that weigh more than .55 pounds but do not have an airworthiness certificate under part 21.
• In addition, for Category 2 operations, no remote pilot in command may operate a small unmanned aircraft in sustained flight over open-air assemblies unless the operation is compliant with Remote ID.
• Category 3 small UAS have further operating restrictions. A remote pilot in command may not operate a small unmanned aircraft over open-air assemblies of human beings. Additionally, a remote pilot in command may only operate a small unmanned aircraft over people if:
  • The operation is within or over a closed- or restricted-access site and all people on site are on notice that a small UAS may fly over them; or
  • The small unmanned aircraft does not maintain sustained flight over any person unless that person is participating directly in the operation or located under a covered structure or inside a stationary vehicle that can provide reasonable protection from a falling small unmanned aircraft.
• Category 4 operations is an addition from the NPRM. This category allows small unmanned aircraft issued an airworthiness certificate under part 21 to operate over people, so long as the operating limitations specified in the approved Flight Manual or as otherwise specified by the Administrator, do not prohibit operations over people. Additionally, no remote pilot in command may operate a small unmanned aircraft in sustained flight over open-air assemblies unless the operation is compliant with Remote ID. To preserve the continued airworthiness of the small unmanned aircraft and continue to meet a level of reliability that the FAA finds acceptable for operating over people in accordance with Category 4, additional requirements apply.

Note: Sustained flight over an open-air assembly includes hovering above the heads of persons gathered in an open-air assembly, flying back and forth over an open-air assembly, or circling above the assembly in such a way that the small unmanned aircraft remains above some part the assembly. ‘Sustained flight’ over an open-air assembly of people in a Category 1, 2, or 4 operation does not include a brief, one-time transiting over a portion of the assembled gathering, where the transit is merely incidental to a point-to-point operation unrelated to the assembly.