A 'partially ionized plasma' such as the Earth s ionosphere is one that also contains neutral atoms. Basically, they are boiling mixes of positive ions and electrons. Reduced Drag With less drag, supersonic airliners might become economically viable, while hypersonic missiles and aircraft flying at more than five times the speed of sound could travel farther on a single tank of fuel. And future generations of space shuttles might rely on plasmas to help them fly during re-entry, which is why NASA is interested. The potential reduction in shock waves is also of interest to the aerodynamicists who design re-entry vehicles and hypersonic aircraft, for whom shock waves are troublesome obstacles in the quest for speed.
Shock waves slow vehicles down, cause terrific heating and create sonic booms.
The way plasmas interact with radio waves around aircraft is causing excitement in the secret world of military aerospace research. Other researchers have found that plasmas can dissipate shock waves from supersonic aircraft, stifling troublesome sonic booms. There are even indications that plasmas might influence airflow at subsonic speeds. If that were the case, tiny plasma generators could replace control surfaces such as ailerons and flaps. Planes of the future might not need any moving control surfaces at all.