Jet engines are powerful machines that propel aircraft by expelling high-speed exhaust gases. They operate on the principle of Newton's third law, where the action of the gases being pushed out results in a reaction that moves the aircraft forward. There are various types of jet engines, including turbojets, turbofans, and turboprops, each designed for specific performance and efficiency needs. The design of jet engines has evolved significantly since their inception, with advancements in materials and technology leading to more efficient and environmentally friendly engines. Modern jet engines are capable of producing immense thrust while minimizing fuel consumption and emissions, making air travel faster and more sustainable.