This only looks like a missile contrail; but it is really a jet.  A jet contrail from December 31, via Contrail Science.

There are multiple hypotheses for the contrail seen near Los Angeles. But the most likely one is pretty boring: It’s a jet contrail viewed from a weird angle.

A jet contrail viewed from just the right angle looks a lot like a missile launch.  There is an actual blog called Contrail Science (How awesome is that!) that is getting slammed with traffic.  The overflow site, though, is still up and I think the author, who is an anonymous pilot, has this one dead to rights. And, of course, there is the Jonathan McDowell rule: When it doubt, just agree with Jonathan, who explains

“If it’s coming over the horizon, straight at you, then it rises quickly above the horizon,” he told New Scientist. “You can’t tell because it’s so far away that it’s getting closer to you – you’d think it was just going vertically up,” he says.

The fact that it occurred at twilight would have emphasised the contrail, he adds. “It’s critical that it’s at sunset – it’s a low sun angle. It really illuminates the contrail and makes it look very dense and bright.”

The short explanation is that we don’t see a lot of jet contrails head-on, especially from the vantage point of a helicopter.  So, it looks like a missile to everyone else, including former Deputy Secretaries of Defense.  But it probably isn’t.

That would explain why no one else in LA saw a missile launch other than the helicopter crew — or, rather, why everyone else from every other angle saw a typical jet contrail — and why DSP didn’t light up like a Christmas Tree.

Update | 4:18 pm 9 November 2009 “There is no evidence to suggest that this is anything else other than a condensation trail from an aircraft,” said Pentagon spokesman Colonel Dave Lapan …