Possible causes of ear aches on board
The air pressure in commercial aircraft can drop to a level corresponding to an altitude of about 2,500 meters above sea level. That can sometimes cause passengers to suffer ear aches.
These occur above all when the balance of pressure between the middle ear and the ambient air pressure cannot function properly. Such complaints can arise in particular if a passenger has a cold with swelling of the nose and the passage between the back of the throat and the middle ear (the so-called Eustachian tube).
Takeoff is less of a problem
An aircraft's takeoff and climb to cruising altitude is less of a problem because the cabin has a subpressure. For a passenger with a cold, the overpressure that arises in the middle ear can then even be balanced relatively easily via the Eustachian tube.
Landing can be painful if you have a cold
The landing presents problems more frequently, because during an aircraft's descent the cabin air pressure increases and the natural balance of pressure can be interfered with due to a cold-related swelling of the mucous membranes. This results in subpressure in the middle ear, with a burden on the eardrums which can be painful.
What you can do to prevent ear aches
The most important technique to enable a balance of pressure is the so-called Valsalva method. Take a breath, hold your nose, and with your mouth closed press the air forcefully to the back of your throat. That opens the Eustachian tube and enables a balance of pressure.
For prevention, you can apply an anti-swelling nose spray to both nostrils about a half-hour before the aircraft begins to descend from cruising altitude. This will free the passages between the nasal sinuses and the middle ear and enable a balance between the ambient pressure and the middle ear.
In addition, you can speed up the pressure balance by making chewing movements. Best of all, take a few bars of chewing gum with you. Deliberate yawning can also reinforce the pressure balance.
In the case of serious inflammatory ailments of the nasal sinuses, you should certainly consult your doctor before your flight.