In-flight research refers to scientific experiments and studies that are conducted aboard aircraft while they are in flight. This type of research allows scientists to explore various scientific phenomena under conditions of microgravity or reduced gravity, which are not easily replicated on the ground. In-flight research can include studies on fluid dynamics, materials science, biology, and human physiology, among others. This type of research is often conducted on parabolic flights, suborbital flights, or aboard specialized aircraft such as the International Space Station. In-flight research provides valuable insights into how physical and biological systems behave in space, and can help inform future space exploration missions.