MDA is a man-made (synthetic) recreational drug noted for its stimulant and psychedelic properties that has been used since the 1960s as a clubbing and sex-enhancing substance, with some similarities to LSD and MDMA (ecstasy). Sought after effects.
The soaring temperatures that Las Vegas is experiencing this week could cause grief for pilots at other airports, because heat thins the air and makes it more difficult for aircraft to lift at take-off. To deal with that, pilots need to gain more momentum as they roll down the runway before reaching liftoff speed.
Varying the air pressure controls the air temperature since the warmed air from the engine bleed moves through the cabin towards the exit valves. Want it warmer, lower the pressure and warmer air fills the cabin. Keep the valves closed for a while and the aircraft cools pretty rapidly and the air does too. Doesn't take much change in pressure to move the air, a few feet of altitude will do it, but the change is what is needed to make the air move at all.