 Additional technologies considered by the ERAST Alliance include lightweight materials, avionics, aerodynamics, and other forms of propulsion suitable for extreme altitudes and duration.Although ERAST Alliance members were responsible for aircraft development and operation, NASA had primary responsibility for overall program leadership, major funding, individual project management, development and coordination of payloads.NASA also worked on long-term issues with the Federal Aviation Administration and developed technology to make operation of these remotely operated aircraft in national airspace practical.