気圧

飛行機でお酒飲むと、気圧のせいか酔いやすい。

Maybe it's the low air pressure that means you get drunk more easily on planes.

ただし押し込む瞬間気圧の変化(へんか)のせいでしょうか、耳がツンとするのが難点です。

However, maybe from the sudden change in pressure when you push them in, having your ears pop is a problem.