So can people look forward to travelling in planes that are almost silent and emit no air pollution?
"Not anytime soon," says Steven Barrett of the Massachusetts Institute of Technology, who reported the results in a study released on Wednesday by the journal Nature.
It's not clear whether the technology could work at such a large scale, he said in a telephone interview. And even if it can, it would take a few decades to develop such planes, he said.
Before that, the approach might be used in airplane-like drones that perform tasks like environmental monitoring and surveillance, he said. As drones become more common in urban skies, the lack of noise would be an advantage in making them less bothersome to people on the ground, he said.
The Nature paper reports the results of 10 test flights inside an MIT athletic building. With a wingspan of about 5 metre, the 2.45-kilogram plane sailed along at about 17 km/h. Each flight covered about 55 meter).
