In consideration of the continuing development of a new generation of supersonic aircraft, FAA is modernizing the procedure for requesting a special flight authorization to operate in excess of Mach 1 over land in the United States. The renewed interest in development of supersonic airplanes caused FAA to review its application procedures that allow for flight tests of these aircraft. This final rule modifies the criteria for applying for these authorizations and moves the material from an appendix to a regulation to make it easier to find and understand. Outside the context of special flight authorizations under this final rule, the FAA continues generally to prohibit civil supersonic flight over land in the United States.