Push-pull aircraft
![](http://upload.wikimedia.org/wikipedia/commons/thumb/f/f4/Cessna_Skymaster_O-2_3.jpg/220px-Cessna_Skymaster_O-2_3.jpg)
A push-pull aircraft is a type of aircraft whose principle is a twin engine. The first engine is propulsion. The second is tractive. The first push and the second pull. On the outside, these aircraft are noticeable by their two propellers: one in front and one in back.