Full FAA Chronology at this link.
19330301: At the Newark Municipal Airport, N.J., the Aeronautics Branch demonstrated a radio system that it had developed for the blind landing of aircraft. The Branch made the system available for service testing by aircraft equipped with the necessary radio receivers. Later that month, Aeronautics Branch pilot James L. Kinney completed the first cross-country test of an all instrument flight and landing when he arrived at Newark from College Park, Md. Kinney was accompanied by Harry Diamond, a Bureau of Standards scientist who helped develop the instrument landing system, and William LaViolette, a radio technician. (See September 13, 1934.)
19370301: The Bureau of Air Commerce commissioned the Los Angeles air route traffic control center on this date, followed by the Washington (D.C.) center on April 1 and the Oakland center on May 15.