> Now - a strong person can do it when the plane is far enough up that it's very scary
Is this true? Some back of the napkin math: An airliner crusing at 30,000 feet is in air at about 0.3 ATM. Cabins are pressurized to about 0.8 ATM, so net air perssure is about 0.5 ATM. That's around 7 lbs/in^2. An airliner door is about 72"x42" for a total of around 3,000 in^2. So you need to be able to lift about 10 tons to open it. That would be a very strong person indeed.
> after all some normal passenger airports are a few thousand feet above sea level
The parent commenter is referring to airports at high elevations. They mean to say that opening the doors is almost impossible at cruising altitude, which is far above any airports. Hence, the doors can only be opened when not on the ground during early ascent and late descent.
You are agreeing with him, he says you can't do it at cruising altitude.
He says you can do it high enough to be scary, but opening the door 100ft before landing would probably cause panic even if it isn't all that dangerous.
Is this true? Some back of the napkin math: An airliner crusing at 30,000 feet is in air at about 0.3 ATM. Cabins are pressurized to about 0.8 ATM, so net air perssure is about 0.5 ATM. That's around 7 lbs/in^2. An airliner door is about 72"x42" for a total of around 3,000 in^2. So you need to be able to lift about 10 tons to open it. That would be a very strong person indeed.