Why do ears pop on airplanes?

Answer: Pressure equalizes through tubes

Altitude affects hearing — Wrong. Altitude doesn't directly affect hearing ability. The popping is about pressure equalization.

Cabin air enters your ears — Wrong. Air doesn't enter your ears from outside; the pop comes from pressure changes inside your middle ear, not from cabin air flowing in.

Pressure equalizes through tubes ✓ — Correct! As altitude changes, air pressure outside differs from inside your middle ear. The Eustachian tube opens to equalize pressure, causing a pop. Swallowing or yawning helps open this tube!