If your Eustachian tube is blocked (due to congestion, allergies, or a cold), it can’t open, creating a vacuum that tugs on your eardrum. "Popping" is simply the sound of the tube opening and pressure equalizing.
For many travelers, the discomfort of "airplane ear" doesn't end when the plane lands. This muffled, full sensation occurs because the air pressure in your middle ear and the cabin pressure didn't quite sync up during descent, causing your eardrum to stretch painfully. how to get ears to pop after flying
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