is self-operating at zero flight speed

is not self-operating at zero^flight speed

requires no air for its operation

produces a jet consisting of plasma

turbo-jet engine

ram-jet engine

propellers

rockets

a propeller system

gas-turbine engine equipped with a propulsive nozzle and diffuse*

chemical rocket regine

ram-jet engine

steam power plant

petrol engine

diesel engine′

gas turbine plant.

less

more

same

may be less or more depening upon speed