; (4) collisions between unmanned aerial vehicles of various sizes, traveling at various speeds, and rotorcraft of various sizes, traveling at various speeds; and (5) collisions between unmanned aerial vehicles and various parts of the aforementioned aircraft, including— (A) windshields; (B) noses; (C) engines; (D) radomes; (E) propellers; and (F) wings. (b) Report Not later than one year after the date of enactment of this Act, the Administrator shall transmit a report summarizing the costs and results of research under this section to the Committee on Science, Space, and Technology of the House of Representatives and the Committee on Commerce, Science, and Transportation of the Senate. 725. Special rule for research and development Except as necessary to support enforcement action under applicable provisions of law against persons operating unmanned aircraft in a manner that endangers the safety of the national airspace system, notwithstanding any other provision of law relating to the incorporation of unmanned aircraft systems into FAA plans and policies, the Administrator may not promulgate any rule or regulation regarding the operation of an unmanned aircraft system— (1) that is flown strictly for research and development use; (2) that is operated less than 400 feet above the ground and in Class G airspace; (3) that is operated in a manner that does not interfere with and gives way to any manned aircraft