The US Naval Research Labs's CICADA (Close-In Covert Autonomous Disposable Aircraft) microdrones are designed to be dropped in bulk from a flying aircraft. Once airborne, the drones use autopilot to stabilize and then GPS and fins to steer to the intended location. Apparently they can glide into a safe landing within 15 feet of their targets. From IEEE Spectrum:
On landing, they transmit data from embedded sensors (a meteorological payload at the moment) back up to their launch aircraft through an antenna embedded in their wings, and each robot will continue to operate and send back data from the ground until its battery runs out…
"Every time I show up at a trade show, or talk with people about CICADA, it's 'oh, could you do this?'," he said. "Chemical and biological sensing is a very interesting idea. There are other electronics you could put in it for seismic sensing along a road. Really, the sky is the limit. It's just a flying circuit board, so anything you can integrate at the component level is fair game…"
"Right now, [CICADAs] would be ready to go drop into a hurricane or tornado," he said. "I really would love to fly an airplane over, and each of these could sample in the tornado. That's ready now. We'd just need a ride. And [FAA] approval."