In this section the following words have the meanings indicated. “Unmanned aircraft” means the flying portion of an unmanned aircraft system, flown by a pilot via a ground control system, or autonomously through use of an onboard computer, a communication link, and any additional equipment that is necessary for the unmanned aircraft to operate safely. “Unmanned aircraft system” means an unmanned aircraft and all the associated support equipment, control stations, data links, telemetry, communications and navigation equipment, and other equipment necessary to operate the unmanned aircraft. Only the State may enact a law or take any other action to prohibit, restrict, or regulate the testing or operation of unmanned aircraft systems in the State. Subsection (b) of this section: preempts the authority of a county or municipality to prohibit, restrict, or regulate the testing or operation of unmanned aircraft systems; and supersedes any existing law or ordinance of a county or municipality that prohibits, restricts, or regulates the testing or operation of unmanned aircraft systems. This section does not affect federal preemption of State law.