That's true however, dextroamphetamine and methamphetamine and extremely similar. There have been multiple studies showing this, although methamphetamine is more potent with regard to oxidative damage.
I believe they're given out quite frequently, aren't they?
Really just depends, in peace time you're not supposed to go past a 24hr duty day, flights would be limited to around 12hrs, and a lot of our stuff still falls under FAA guidelines, but obviously there's training missions that go over it. But yes, in war time and anytime long flights are needed pilots get stimulants, and lots of piss bags. 24hour plus workdays weren't uncommon during the thick of it whether in the air or on the ground.
When flying fighters to the sand box they'd fly to Maine, aerial fuel across the pond to Spain, Italy, aerial fuel into Iraq or Turkey if final was into A-Stan. So they got to stop every day and sleep, getting to Asia is even more fun.