飛行機でお酒飲むと、気圧のせいか酔いやすい。

、。

When you drink alcohol on an airplane, you get drunk easily — maybe because of the air pressure.

Literal

Airplane [by-で] alcohol drink [if-と], air-pressure [blame-のせいか] get-drunk-easily.

A natural, casual observation. ~のせいか means 'maybe because of' — せい marks cause/blame, か adds uncertainty. 酔いやすい uses ~やすい ('easy to') with 酔う ('to get drunk'). Particle omission (お酒を → お酒) is standard in casual speech.