Different airliners are optimized for different cruise speeds, too. Large planes like the 747 and A380 tend to fly faster by default than smaller planes like the 737.
A large passenger jet with an airspeed close to Mach 0.9 in strong tail wind can sometimes show ground speed very close to, or even a bit over, what we normally take as Mach 1.
A large passenger jet with an airspeed close to Mach 0.9 in strong tail wind can sometimes show ground speed very close to, or even a bit over, what we normally take as Mach 1.