The propulsion to reach space may be purely rocket based or may use the assistance of air-breathing engines.

Kerbal Space Program - initially space-focused, but the addition of air-breathing engines and lift surfaces made atmospheric flight practical.

The X-43A is the first aircraft to reach hypersonic speeds using an air-breathing engine.

In this article, we'll take a look at hypersonic planes and learn about their air-breathing engines.

The airplane elements can be wings, air-breathing engines, or both.

If the pressure-vessel is carbon fiber/epoxy the weight-to-power ratio is said to be comparable to an air-breathing engine with fuel tanks.

For air-breathing engines the effective exhaust velocity is not physically meaningful, although it can be used for comparison purposes nevertheless.

Immediately after the vehicle reaches the desired altitude, the air-breathing engine will be detached.

The exact formula for air-breathing engines moving at speed with an exhaust velocity is given in the literature as:

Since a torpedo cannot have an air-breathing engine like a boat, how is it propelled through the water?