Full FAA Chronology at this link.
19470404: The Convention on International Civil Aviation came into force after being ratified by 26 countries. (Among these was the United States, which had ratified the Convention on August 9, 1946.) The Convention had been drawn up at a conference in Chicago over two years before (see November 1-December 7, 1944). The fact that it was now in force officially created the International Civil Aviation Organization (ICAO) to succeed its temporary predecessor, PICAO (see June 6, 1945). The first General Assembly of ICAO was held in Montreal during May 6-28.
19470404: CAB certificated Piedmont Airlines as a local service carrier. The airline, whose original routes ran along the Piedmont-Appalachia area, began operations on February 20, 1948. Piedmont expanded steadily during the succeeding decades, then grew rapidly after