What must a ground crew obtain before landing an aircraft on someone else's property?

Before landing an aircraft on someone else's property, it is essential for the ground crew to obtain permission from the landowner. This is primarily rooted in property law and the rights of landowners over their property. Landowners have the right to control access to their land, and unauthorized landings can be considered trespassing. Therefore, seeking permission before landing is not only a matter of courtesy but also a legal requirement to avoid potential disputes or legal actions from the landowner.

In this situation, the other options do not adequately address the necessity of obtaining rights related to private property. A permit from the FAA is typically concerned with ensuring that the aircraft meets safety and operational regulations, but it does not grant landing rights on private property. A notice of intent, while potentially relevant in certain regulatory contexts, does not convey the essential permission needed for private property use. Clearance from air traffic control is focused on airspace management and safety during flight but is separate from property rights and does not confer authority over where a plane can land when not on designated airfield grounds.