Many of NASA’s most important aerospace breakthroughs that began in the laboratory were ultimately proven in the sky. For decades, experts at NASA’s Glenn Research Center in Cleveland conducted flight tests — piloting aircraft into targeted environments such as icing clouds and carefully defined atmospheric routes. This approach allowed them to collect measurements directly in flight, providing critical data that linked laboratory theories to practical performance. 

The center’s flight research dates to the 1940s, when NASA Glenn was known as the Aircraft Engine Research Laboratory for the National Advisory Committee for Aeronautics, NASA’s predecessor agency. During World War II, engineers and pilots worked to improve aircraft performance and increase high-altitude reliability. In the mid-to-late-1940s, flight research helped make early jet and ramjet engines practical. Later, Glenn’s flight programs helped improve the efficiency and environmental performance of aircraft engines — primarily conventional jet engines. 

Behind those early flight programs was a pioneering group of pilots who helped establish NASA Glenn’s reputation for airborne research. The center’s first generation of pilots, including Howard Lilly, Joseph Walker, William Swann, and William “Ed” Gough, helped lay the groundwork for more than two dozen other Glenn pilots, including future astronauts Neil A. Armstrong and Fred Haise. 

Together with Glenn’s researchers, engineers, and support staff, these pilots established airborne research capabilities that NASA continues to rely on today. Their work demonstrated how flight testing could bridge the gap between laboratory research and real-world performance. 

“These missions transformed aircraft into flying laboratories,” said Mark Russell, a NASA safety officer and pilot who served as the former acting chief of Aircraft Operations at Glenn. “They bridged the gap between ground testing and full-scale flight, proving the measurements needed to connect theory with performance. The testing also helped validate technologies and procedures later used aboard spacecraft and orbital missions.” 

Research workhorses 

From the start, NASA put its aircraft to work on a wide range of research challenges. 

For decades, NASA Glenn aircraft have been used to study in-flight icing hazards, collecting data that has helped make commercial aviation safer. For nearly 40 years, NASA Glenn’s De Havilland DHC-6 Twin Otter served as the center’s workhorse for icing research, gathering data that helped shape modern aviation safety standards. 

Beyond improving aviation safety, Glenn’s flight research also explored new propulsion technologies that could transform the future of flight. Today, researchers are exploring hydrogen as an aviation fuel. But NASA Glenn helped show its potential viability decades ago using its Martin B-57B Canberra aircraft. After developing a hydrogen fuel system for the B-57B, a team tested it safely from February to April 1957. The flights showed the system’s reliable operation and advanced efficiency, marking a major milestone in aviation technology.  

Flight testing also supported technologies destined for use beyond Earth, helping researchers evaluate hardware under conditions that closely resembled space. Beginning in 1963, the center began a program to test and measure how well solar cells worked under conditions similar to those in space. Using specially modified airplanes, including Learjets, NASA conducted flights to help recreate some of the sunlight and atmospheric conditions that solar cells would experience outside Earth’s atmosphere. The program lasted decades, supporting space technology calibration through numerous high-altitude flights and adapting to newer aircraft over time. 

Researchers later applied these airborne capabilities to environmental science, extending their value beyond aviation and space technology. Using the Twin Otter and S-3B Viking over the Great Lakes, researchers tracked harmful algal blooms on Lake Erie by measuring changes in water color and composition. The data improved satellite systems used to monitor water quality and ecosystem health.  

Glenn’s research aircraft also played an important role in preparing technologies and experiments for spaceflight through microgravity testing. NASA Glenn advanced microgravity research through in-flight testing using specially modified aircraft, such as its DC-9, to create short periods of weightlessness during parabolic maneuvers. These flights allowed researchers to study how fluids, combustion, materials, and experimental equipment behaved in near-zero gravity before experiments were conducted in space.  

Recent breakthroughs 

Other significant accomplishments enabled by Glenn’s flight research include supporting the development and testing of sustainable aviation technologies, including research related to more fuel-efficient engines and sustainable aviation fuels, and advancing in-flight instrumentation and measurement techniques used across aeronautics research. 

In 2024, Glenn’s Flight Operations participated in an optical communications study using the center’s Pilatus PC-12 NG aircraft. This mission successfully demonstrated the ability to transmit large volumes of data through a laser communication system across NASA’s legacy infrastructure. The work contributed to NASA’s broader effort to advance optical communications for future missions. NASA further tested optical communications on the Artemis II mission and effectively transmitted substantial amounts of data from the Orion capsule to multiple ground stations over the course of the 10-day journey.  

As NASA’s flight research enterprise evolved, the agency also restructured how it manages its research aircraft. In October 2025, NASA streamlined its aircraft flight operations, relocating its aircraft from Glenn to NASA’s Armstrong Flight Research Center in Edwards, California. NASA Glenn continues its important icing and propulsion research and communications technology development in collaboration with Armstrong.  

From its historical roots in wartime engine development to modern work on aircraft safety, Glenn’s airborne research has consistently moved innovative ideas from the laboratory to real-world application. For more than eight decades, NASA Glenn has transformed ideas first proven in the laboratory into innovations validated in the sky — a legacy that continues to shape the future of aviation and space exploration.