On August 17, the federal district court in New York enjoined¹ the Port Authority of New York and New Jersey from banning test flights of the Concorde SST into John F. Kennedy (JFK) International Airport because of the plane's noise impacts after finding the ban to be an unreasonable exercise of the proprietary powers of airport owners. This decision, along with an earlier Second Circuit ruling remanding² the case to the district court for a factual determination as to whether the ban constituted an unreasonable burden on interstate commerce, adds an interesting gloss limiting the proprietary regulatory powers implicitly left to municipal airport operators in the Supreme Court's 1973 decision in City of Burbank v. Lockheed Air Terminal.³