Today, there are ten Russian Mig 31 aircraft that are on experimental combat duty and are ready to use the hypersonic mach 10 Kinzhal depending on the situation. (Source : Russian deputy defense minister Yury Borisov at the Russian Star)
The Mig 31 is capable of cruising at Mach 2.35 with an air-to-air payload and is temperature limited to Mach 2.83.
The Khinzal missile flies 10 times faster than the speed of sound and can also maneuver at all phases of its flight trajectory. This allows it to overcome all existing and most prospective anti-aircraft and anti-missile defense systems, delivering nuclear and conventional warheads in a range of over 2,000 kilometers.
There are some US “experts” who want to claim that the US is not behind with hypersonic weapons. Russia and China have deployed hypersonic missiles. The US has no hypersonic weapons deployed and are unlikely to deploy before 2020-2023.
The US is currently behind in hypersonic weapons.
The US Air Force is talking about faster hypersonic weapon prototyping in order to catch up.