If you're still scratching your head over that large, loud, low-flying object that orbited around Altadena twice last Saturday afternoon, there may be an answer. The aviation buffs on the Chaney Trail discussion group have identified it as a C-17 military cargo plane.
We don't get that kind of aircraft much in these parts, altho' we do get the B-2 Stealth bomber a couple of times a year, flying over the Rose Bowl parade or winging its way to an appearance at the Hollywood Bowl Independence Day show.
So what was a C-17 doing here, besides rattling the windows at Altadenablog World Headquarters? Best guess is that it was appearing in the Miramar air show.