From a 2007 story in the Washington Post, "Dragonfly or Insect Spy? Scientists at Work on Robobugs" http://www.washingtonpost.com/wp-dyn/content/article/2007/10... :

   Vanessa Alarcon saw them while working at an antiwar rally in
   Lafayette Square last month.

  "I heard someone say, 'Oh my god, look at those,' " the college
  senior from New York recalled. "I look up and I'm like, 'What the
  hell is that?' They looked kind of like dragonflies or little
  helicopters. But I mean, those are not insects."

  Out in the crowd, Bernard Crane saw them, too.

  "I'd never seen anything like it in my life," the Washington lawyer
  said. "They were large for dragonflies. I thought, 'Is that
  mechanical, or is that alive?' "

  That is just one of the questions hovering over a handful of similar
  sightings at political events in Washington and New York. Some
  suspect the insectlike drones are high-tech surveillance tools,
  perhaps deployed by the Department of Homeland Security.