ENID, Oklahoma - Pilots from all over the world train at Vance Air Base. Last Quarter, Vance had the busiest runway in the entire Air Force.

The first stop for pilots is "Aerospace and Operational Physiology," where they learn how their bodies will react when in the air.

Before pilots and crew get comfy here, they get not so comfy.

"Special disorientation, unfortunately we can't train that way," Major Mike Akins said.

Instead, those in training acclimate to high altitude flights without leaving the ground. It happens inside this 60 year old hypo-baric chamber.

"The Chamber in creative pump, and create a vacuum of the chamber, like the vacuum of high altitude," Akins said.

Airman Thomas Griesemer is taking a flight. He came all the way from Rhamstein Air Base in Germany for the training.

Right now, he is breathing the air of 25,000 feet. Mount Everest is just a little higher at 29,000 feet. Breathing this air for several minutes can produce some strange behavior.

The final test is rapid decompression.

Griesemer does just fine. Soon, more students will arrive at Vance, ready to learn lifesaving lessons, and taking flight on their own.

Aerospace and Operational Physiology also teaches students how to safely land to the ground if forced to parachute out of a plane.