Your ears get blocked where there’s a pocket of air inside the middle ear, behind the eardrum.

When you swallow, a small bubble of air passes from your throat or back of your nose through a narrow tube known as the Eustachian tube, into your middle ear. As it does this, it makes a tiny click or popping sound. This action keeps the air pressure on both sides of the eardrum about equal. If the air pressure isn't equal, the ear feels blocked.

Usually, the air in the middle ear will be constantly absorbed by the membranes that line the cavity, so internal pressure is easily lowered. This pocket of air is particularly sensitive to changes in air pressure. The higher the plane, the lower the air pressure around you. Although cabin pressure is regulated, it still does not cancel out all the effects, and your ears will still get blocked.

To relieve this problem, try swallowing because it activates the muscle that opens the Eustachian tube. Chew gum or suck on sweets during ascent and descent.