Much of modern air travel uses jet engines which relies on the compression and combustion of fuel in air to produce thrust; a noisy affair. There exists another kind of engine though that could produce the needed thrust, but it has not been scientifically explored for many reasons. Researchers at MIT however have decided to test this other kind of engine, the ionic thruster, and found some very interesting results.
With a high enough voltage, it is possible to ionize the air around one electrode and drive it to another. As the ionized air moves, it will push other air molecules as well, creating thrust, and this method of propulsion has been used for years in small vehicles. The researchers decided to test its efficiency, compared to modern jet engines, and found that while a jet engine will produce 2 Newtons of thrust per kilowatt (Newton is a measure of force) an ionic thruster can produce 110 N of thrust per KW. Importantly the ionic thrust is very efficient at lower thrust, which wastes less energy in your wake.
As impressive as the results may be though, it will still be a long time before any large vehicle would use ionic thrusters because the power requirements can be enormous. Potentially a thrust to drive an aircraft could need over a hundred kilowatts, or even megawatts of power, and generating that much power onboard an aircraft is not going to be easy, but thanks to this study, others are looking into the technology.