In the context of aviation and aerospace, "Active" can refer to several concepts, including:

1. Active Aircraft or Spacecraft: A vehicle that is currently in operation, flight, or mission mode, as opposed to being in storage, maintenance, or inactive status.
2. Active Controls: Flight control systems that are electronically or mechanically controlled to provide stability, maneuverability, and control of the aircraft or spacecraft. Examples include fly-by-wire systems and active ailerons.
3. Active Safety Features: Systems designed to prevent accidents or mitigate their effects, such as automatic emergency oxygen systems, collision avoidance systems, or terrain awareness warning systems.
4. Active Navigation: Navigation systems that use real-time data and sensors to provide precise location, altitude, and velocity information, such as GPS, inertial navigation systems, or terrain-following radar.
5. Active Surveillance: Radar, electronic support measures, or other sensors used to detect and track aircraft, spacecraft, or other targets in real-time.
6. Active Flight Control: A system that uses real-time data from sensors and flight control computers to adjust the aircraft's flight path, altitude, and attitude.
7. Active Launch or Recovery: The process of launching or recovering a spacecraft, satellite, or aircraft, which requires active systems to control the vehicle's trajectory, velocity, and attitude.
8. Active Pilot or Astronaut: A pilot or astronaut who is currently flying or operating an aircraft or spacecraft, as opposed to being a passenger or in a non-flying role.

These are just a few examples of the many ways "Active" can be applied in the context of aviation and aerospace. The specific meaning depends on the context in which it is used.