Aircraft like the the 787 Dreamliner and SUGAR concept are far more fuel efficient than conventional airliners while the all-electric Ce-Liner does away with jet fuel altogether, Unfortunatley the only practical way to propel an aircraft at the moment with electricity is to use a propeller.
While Props might be acceptable for single seater and low speed aircraft they will never provide air speed comparable to a modern day jet engine. So the question can be asked, is there any EV alternative to the fossil/bio fueled jet engine? Recent tests conducted at MIT suggest that tomorrow's planes could take flight using an ionic breeze.
Officially known as electrohydrodynamic thrust, A basic ionic thruster consists of three parts: a very thin copper electrode, called an emitter; a thicker tube of aluminum, known as a collector; and the air gap in between. A lightweight frame typically supports the wires, which connect to an electrical power source. As voltage is applied, the field gradient strips away electrons from nearby air molecules. These newly ionized molecules are strongly repelled by the corona wire, and strongly attracted to the collector. As this cloud of ions moves toward the collector, it collides with surrounding neutral air molecules, pushing them along and creating a wind, or thrust.
According to a study recently published in the Proceedings of the Royal Society, MIT researchers have experimentally demonstrated that an ionic engine could produce up to 110 N/kW of thrust compared to the 2N/kW that jet engines generate. Surprisingly, they discovered that an ionic engine runs most efficiently at lower thrust levels.
"If you have a high-velocity jet, you leave in your wake a load of wasted kinetic energy," assistant professor of aeronautics and astronautics Steven Barrett told the MIT press. "So you want as low-velocity a jet as you can, while still producing enough thrust." What's more, ionic engines are both silent and invisible on infrared since they done produce heat which makes them perfect for stealthy surveillance aircraft and ISR drones.
There's still quite a ways to go before these engines actually take to the sky. Engineers must first solve issues of thrust density (the amount of thrust generated per area unit) the related problem of producing enough voltage to sufficiently power the system, and of course energy storage.