Which engine type is primarily used in commercial aviation for high-speed jets?

Turbojet engines are primarily used in commercial aviation for high-speed jets due to their ability to provide high thrust at high speeds. These engines operate on the principle of air being compressed, mixed with fuel, and ignited, producing a high-velocity exhaust that propels the aircraft forward. They excel in cruising at supersonic speeds, making them ideal for commercial jetliners and military aircraft that require speed and performance.

In contrast to turbojet engines, reciprocating engines, which are more common in smaller aircraft, operate by using pistons and are generally less efficient at high altitudes and speeds. Turboprop engines, while they are efficient for regional and short-haul flights, are designed more for low-speed operations and are not as effective in high-speed jet applications. Hybrid engines, which combine different propulsion systems, are still in developmental stages and are not widely used in commercial aviation, making them less relevant at this time. Thus, the correct focus on turbojet engines highlights their specific advantages for high-speed jet performance in commercial aviation.