Two F-16 fighters under the direction of NORAD intercepted a GA aircraft in the vicinity of northeast Los Angeles at approximately 0945 PDT.
The fighters responded to a temporary flight restriction violation by a Piper 28 aircraft. After intercepting the aircraft, the F-16s followed it until it landed at El Monte airport without incident at approximately 0950, where the plane was met by local law enforcement.
UPI reports that the pilot was arrested and interviewed by Secret Service agents. His violation of the TFR was apparently caused by his failure to check NOTAMS, and not a threat to the President.
The Presidential visit had a great deal of the airspace around LA on lockdown. But this violation did not end with the pilot under arrest for transporting marijuana in his plane, as was the case with a similar incident which occurred in LA in February.