There was a fairly massive flyover of vintage aircraft, some flying in formation, in the south apparently over Pasadena, lasting from about 5:50-6 PM.  We're throwing it out to our aviation fans in hopes they'll give us an answer!

 UPDATE:  we knew we could count on our readers! The city of Burbank is celebrating its 100th birthday, and the flyby was to celebrate Bob Hope Airport.  The planes included a twin-tailed P-38 (which we could identify, and which totally exhausts our knowledge of WWII planes).