Why Don't Commercial Planes Fly Faster?

The main reason commercial aircraft have not gotten any faster in recent decades is due to fuel efficiency. Airplanes consume more energy the faster they fly, so airplane manufacturers favor slower speeds to save on operating costs. Furthermore, a modern air passenger has much less incentive to shell out more money to travel faster. It’s interesting to note that airplane manufacturers are technically capable of producing faster commercial planes, but there simply isn’t much demand for them outside of military applications. Moreover, as planes become faster, they inevitably tend to become more noisy, particularly when they break the sound barrier. This conflict is something that manufacturers want to avoid.