Once the plane is in the air? Fantastic! It’s when the plane is on the ground and the main power and filtration is off is where the danger is. On my last few

Once the plane is in the air? Fantastic! It’s when the plane is on the ground and the main power and filtration is off is where the danger is. On my last few flights I’ve brought a high quality co2 meter and it consistently hit 3000-5000PPM in the time between boarding and when the plane was moving.