Loons, gulls, puffins, and kingfishers all share a remarkable ability: they can dive into water, swim after prey, and then launch themselves back into the sky. For engineers, reproducing this seamless transition between air and water has been a long-standing challenge because the two mediums are so different — water is roughly 1,000 times denser than air.
Now a team led by Raphael Zufferey, assistant professor of mechanical engineering at MIT, has cracked the problem. Their creation, called a flapping-wing aerial-aquatic vehicle (FAAV), weighs less than 300 grams — about half a pound — and is roughly the size of a puffin. The results were published in the journal Science on July 9, 2026.
How it works. The robot's body houses a waterproof electric motor driving a crankshaft that flaps the wings up and down. The wings are coated with hydrophobic nanoparticles that shed water on takeoff. A motorized tail adjusts its angle to control ascent and descent. The team tested different wing sizes, flapping frequencies, and tail angles in both a water tank and a local lake, identifying the exact combinations that allow smooth transitions from swimming to flying.
Inspired by real birds. The researchers analyzed scientific data on puffins, petrels, and other diving birds, finding that smaller birds flap about 10 times per second in air and roughly 4 times per second underwater. The robot was built to match these frequencies, enabling it to swim at 3 meters per second and fly efficiently through the air.
Real-world applications. The team envisions these winged robots being deployed for oceanography, marine biology, and coastal monitoring. A scientist could launch one from a boat, fly it to a pod of whales or an iceberg, dive it underwater to collect a sample or take a measurement, then fly it back — all at a fraction of the cost of deploying a research vessel or a multi-vehicle system.
The design is also remarkably simple and cheap to build, opening the door to a new class of aerial-aquatic drones that could help monitor fragile ocean environments, inspect offshore infrastructure, and study wildlife without disturbing it.