Interestingly, fighter pilots do take amphetamines - a prescribed drug otherwise known as speed. They are a standard prescribed issued drug to fighter pilots who need to stay awake on long missions. This is because regular caffeine pills aren’t enough to keep someone awake and alert enough to fly and control aircraft.
The Air Force calls the amphetamines “go pills” to keep them going. There was a ban up until 1992, where the speed pills were slowly reintroduced to help the fighter pilots function during long missions.
Unfortunately, there have been cases of psychological addictions to the speed pills during the Gulf War and other wars, so they are carried more as a last resort than anything else. They aren’t required to take amphetamines due to the addictive value, however, some missions do require “go pills” to be taken. This is because some pilots might not be fit enough to work for up to 9 hours at once.
In short, fighter pilots do take speed if they are taking part in long and intense missions and need to stay alert. However, this is not for recreational purposes and must be taken seriously due to the risk of addiction and psychological problems.