A pusher aircraft is a type of aircraft using propellers placed behind the engines and may be classified according to engine/propeller location and drive as well as the lifting surfaces layout (conventional or 3 surface, canard, joined wing, tailless and rotorcraft), Some aircraft have a Push-pull configuration with both tractor and pusher engines.
The list includes these even if the pusher engine is just added to a conventional layout (engines inside the wings or above the wing for example).
The conventional layout of an aircraft has wings ahead of the empennage.
A tandem layout has both front and rear wings of similar dimensions.
Tailless aircraft lack a horizontal stabilizer, flying wings lack a distinct fuselage, with crew, engines, and payload contained within the wing structure.