Future --- Air-Breathing Rocket

NASA engineers have designed a new rocket engines that eliminates the need for onboard oxidizer for the purpose of lightening the load of spacecraft at launch.
Air-breathing engines, work similarly to ordinary rocket engines but obtain their oxygen from the atmosphere, much in the same way as a jet engine. Since a spacecraft with such an engine would not have to carry the oxidizer, it would weigh far less, be much easier and cheaper to get into orbit.

The Engine of the Air-Breathing Rocket
Lift-off

Air-Breathing Rocket Space Elevator Space Plane