Healthy Flights Act of 202 1 This bill provides authority for the Federal Aviation Administration (FAA) to impose requirements on passenger and cargo air travel to protect the health and safety of air carrier crewmembers and passengers and to reduce the spread of infectious diseases through the aviation system during public health emergencies. For example, the bill (1) sets forth requirements relating to the use of masks and other protective equipment for airline passengers and certain airline employees; (2) requires the FAA to provide certain employees, including any air traffic controller and airway transportation systems specialists, with masks and other protective equipment; and (3) mandates the development of a national aviation preparedness plan to ensure the aviation system is prepared to respond to epidemics and pandemics of infectious diseases. Additionally, the bill directs each air carrier operating an aircraft with a seating capacity of 20 or more to implement appropriate measures on a flight to reduce the likelihood of any passenger or crewmember contracting an infectious disease. The FAA must enter into an agreement with the National Academies to conduct a study on the transmission of infectious diseases, such as respiratory diseases, in the cabins of passenger airplanes. Further, the bill (1) establishes a Center of Excellence for Infectious Disease Response and Prevention in Aviation within the FAA; and (2) directs the FAA to revise airline passenger briefing requirements, including briefings during a national emergency pertaining to a respiratory disease.