Even though it’s blatantly against the unwritten rules of flying to over-indulge in alcoholic beverages on a plane, some people decide 30,000 feet is the perfect place to get turnt. And though that pariah on the plane knows full well he’s drinking irresponsibly, he’ll still going to try and justify it by saying something like “Sorry, man! One drink up here is equal to, like SIX on the ground!”
But it turns out that excuse, to put it delicately, is utter horseshit.
Some people drinking on airplanes -- or just having their first double IPA upon landing in Denver -- think altitude is the express train to Tipsytown, but science says otherwise. The FAA has studied this phenomenon and keeps finding that altitude has little if any effect on relative intoxication. (Whether you feel more impaired may be another matter. More on that a little later.)
The first FAA study, done in the 1970s, assigned a group of men cognitive tasks at 1,300 feet and with oxygen levels that mimicked 12,500 feet in altitude, both with and without the confidence-building benefit of a screwdriver. Though booze definitely affected how well the men performed the tasks -- “alcohol at ground level resulted in significantly impaired performance” -- the change in altitude didn’t worsen their cognitive decline. In 1985 the FAA repeated the study, and arrived at pretty much the same results.
Granted, planes fly at 30,000 feet, so one might reason the effects would be stronger. But the air in planes is pressurized to oxygen levels of about 10,000 feet.