Aeronautical engineers work on airplanes; that is, they design and test vehicles that fly in the Earth’s atmosphere. Drones, helicopters, commercial aircraft, fighter jets and cruise missiles are among the aviation engineers’ terms of reference. The aerospace engineer is responsible for the design, development and testing of vehicles leaving the Earth’s atmosphere. This includes a variety of military, government and private sector applications such as rockets, missiles, spacecraft, planetary detectors and satellites. These two sub-areas overlap quite a bit in the skill set they need, usually both in the same department of the university. The largest employers of aerospace engineers often have products and research involving aerospace and aerospace. Boeing, Northrop Grumman, NASA, SpaceX, Lockheed Martin, JPL (Jet Propulsion Laboratory), General Electric and several other companies are also the same. The nature of aerospace engineering work varies widely. Some engineers spend most of their time in front of computers that use modeling and simulation tools. Others work more in air tunnels and on-site test scale models as well as on actual aircraft and spacecraft. It is also common for aerospace engineers to participate in evaluating project proposals, calculating security risks and developing manufacturing processes.