This Guardian article quotes the "food babe". Food babe also had this to say about flying on airplanes "The air that is pumped in isn’t pure oxygen either, it’s

This Guardian article quotes the "food babe". Food babe also had this to say about flying on airplanes "The air that is pumped in isn’t pure oxygen either, it’s mixed with nitrogen, sometimes almost at 50%. To pump a greater amount of oxygen in costs money in terms of fuel and the airlines know this!" (actual nitrogen percentage in air: 78%)