It turns out that plane that flew low over Manhattan this morning was just President Obama's back-up plane; it was on a mission so that Air Force photographers could take pictures of Lower Manhattan. Officials in Washington say they informed City Hall and the NYPD about the plan in advance, although the NYPD now says it was prohibited from alerting the public. So, as a result, everyone who saw the plane freaked out, several office buildings were evacuated, and nervous traders sent the stock market plunging for several minutes until they found out that it wasn't a terrorist attack. Sure hope the photos were worth it! [NYT/CityRoom]