No, commercial passenger jets typically do not reach Mach II+ speeds during cruising flight. The cruising speeds of commercial passenger jets are usually subsonic, which means they fly below the speed of sound.
Most commercial airliners, such as Boeing 747, Airbus A320, or Boeing 787, have cruising speeds that range from Mach 0.8 to Mach 0.85, which is roughly 530 to 570 miles per hour (853 to 918 kilometers per hour). These speeds are significantly below the speed of sound, which is approximately Mach 1.
There are a few reasons why commercial passenger jets do not typically fly at supersonic speeds:
Fuel efficiency: Flying at supersonic speeds requires a significant amount of additional fuel due to increased drag and resistance. Supersonic flight is more fuel-intensive compared to subsonic flight, making it economically impractical for commercial aviation.
Sonic boom: Supersonic flight generates a sonic boom, which is a loud noise caused by shockwaves when an object exceeds the speed of sound. Sonic booms can be disruptive and potentially damaging to structures on the ground. Consequently, regulations restrict supersonic flights over land for commercial airliners.
Structural considerations: Designing an aircraft that can withstand the stresses and aerodynamic challenges of sustained supersonic flight requires specialized engineering and materials. Such aircraft are typically purpose-built for supersonic or hypersonic flight, like military jets or experimental aircraft.
While there have been efforts to develop supersonic commercial aircraft, such as the Concorde that operated from 1976 to 2003, these projects have not yet resulted in widespread commercial supersonic travel. However, there are ongoing initiatives to develop new supersonic and even hypersonic commercial aircraft, but their implementation and feasibility are still being explored.