Q: Is it a bird? Is it a plane? A: Neither – it's a microdrone

The enemy might look up and ask if it's a bird, a plane or Superman. Soon, however, it might be a mechanical insect with flapping wings, transmitting sound and images back to commanders in the United States. And if it's not zipping through the air it could instead be perching quietly on a window sill near you.

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In recent years the US Army and Air Force have grown ever more dependent on unmanned aircraft, known as drones, to spy on and fire missiles at America's foes, and the Pentagon is now moving quickly to develop new generations of the machines, some of which will be as small as dragonflies. Research into new types of drones is moving at full tilt in a facility at Wright Patterson Air Force Base in Ohio, where the next big goal is the development of miniature drones that will use "flapping wing" technology to stay aloft and be able to land almost anywhere, hopefully undetected. Greg Parker, an aerospace engineer at the base, told The New York Times: "We're looking at how you hide in plain sight."

Researchers say that while work has been done on replicating the mechanics of bird flight, the actions of an insect's wings are easier to copy and translate into moving parts.

So intense is the focus on developing insect-like drones now that the warehouse where the research is being pursued has been called the "micro-aviary". One focus is developing drones that will have wings based on those of a hawk moth. "It's impressive what they can do compared to what our clumsy aircraft can do," said Major Michael Anderson, who is assigned to the base.

Drone technology has become ever more crucial to US forces in arenas as far apart as North Korea (where they carry out surveillance of nuclear activities), Libya, Iraq and of course Afghanistan. While a decade ago the US had fewer than 50 unmanned aircraft ready for deployment, today it has as many as 7,000 of them. Best known to the general public is the Predator drone, which is about the size of a small propeller plane. It is flown remotely by pilots in front of computer screens with joysticks, usually in the US, who can both watch the enemy and fire upon it. Today, the US Air Force has more pilots training to fly drones than to fly manned aircraft.

But there is a wide range of other drone models in service, including blimp-like machines that are tethered and provide stationary surveillance platforms, and tiny toy-like remote-control aircraft that can be pitched into the air like a ball by soldiers, moving forward to tell them what might be lurking around the next corner or over the next hill. Called Ravens, these are in use by US forces in Afghanistan.

The Pentagon has asked Congress for $5bn to expand its drone fleet in the coming year. While insect drones are not yet off the drawing board, in February the US Air Force began testing a prototype hummingbird drone developed by AeroVironment, the private company which makes the Raven. Four inches long, it is said to be capable of hovering and flying forward at 11mph thanks to flapping wings.