NASA is usually associated with spaceflight, but its first "A" stands for Aeronautics. NASA conducts aeronautical research and works to improve the safety of air transportation. Aeronautics research was initially carried out by the NACA, or the National Advisory Committee for Aeronautics. Created in 1915, the NACA was absorbed by NASA in 1958 at the onset of the Space Race, when the need for astronautical research increased. 

Throughout the latter half of the 20th century, Dr. Richard T. Whitcomb of NASA led the development of several key technologies: area rule in the 1950s and '60s, supercritical wings in the 1970s, and winglets in the 1970s and '80s. All help reduce aerodynamic drag and therefore increase fuel efficiency and range. 

Area Rule 

Whitcomb’s concept, called area rule, was first applied to jet fighters (producing their distinctive "Coke-bottle" shape) and later to such airliners as the Boeing 747, Douglas DC-8, McDonnell Douglas DC-10, and Concorde. Area rule involves creating a more consistent total cross section by narrowing an aircraft's fuselage where the wings join the body reduces drag at high speeds.  

The Convair 990 used NASA-designed anti-shock bodies, or "speed pods," on each wing to reduce drag at high subsonic speeds. The pods used area rule to improve the aircraft's performance and to allow the 990 to cruise at Mach .91, just below the speed of sound. 

The Supercritical Wing

Another technology developed under Whitcomb was the supercritical wing. A supercritical wing delays the formation and reduces the size of shock waves over the wing at transonic speeds (just below and above the speed of sound), the speeds which most jetliners fly. All new large jetliners now feature this highly efficient, drag-reducing wing design. 

Grooved Runways 

During the 1960s, NASA developed grooved runways to channel away water and improve traction for aircraft. By reducing the effects of hydroplaning, grooved runways minimize the chance of aircraft sliding off a wet runway during landing. This proved so successful that the technology has since been applied to highway design to improve safety.

Winglets 

Towards the end of Whitcomb’s professional career in the 1970s and 80s, he led the development of winglets. Winglets were small vertical fins on wingtips-reduce the strength of wingtip vortices (air swirling off the ends of the wings). Most airliners feature some type of winglet to help decrease drag. 

NASA (and its predecessor, the NACA) has created several revolutionary aeronautical technologies that have made air travel safer, more efficient, and less expensive. Today's generation of highly productive airliners has directly benefited from NASA's pioneering research.