14 CFR 101.23 - General operating limitations.
(a) You must operate an amateur rocket in such a manner that it:
(1) Is launched on a suborbital trajectory;
(2) When launched, must not cross into the territory of a foreign country unless an agreement is in place between the United States and the country of concern;
(3) Is unmanned; and
(4) Does not create a hazard to persons, property, or other aircraft.