Hi. Seems like you have developed a eustachian tube (ET) dysfunction due to high altitude travel. This may worsen during the takeoff or landing of your flight in the coming days and may have an effect on your hearing. The eustachian tube (ET) connects the back of the nose to the middle ear region (This explains why you hear a popping every time you swallow or blow your nose). The ET is important for equalizing the pressure between the ear and the atmospheric environment. During high altitudes such as in the mountains or during ascent or descent in an aircraft, due to negative cabin pressure, the ET collapses and creates blockage leading to a negative pressure within the ear which pulls the ear drum inwards leading to pain and feeling of blockage. Middle ear produces mucus and secretions which drain into the nose through the ET. When the ET is blocked, this fluid accumulates inside the middle ear and creates the feeling of fluid in the ear. ET dysfunction is treatable if the ET is blocked by a mucous plug or swelling. The mainstay of treatment is opening the ET. Toynbee maneuver can be tried 3-4 times a day for about a week to help unclog the ET. The maneuver involves pinching the nose and swallowing. Swallowing pulls open the eustachian tubes while the movement of the tongue, with the nose closed, compresses air which passes through the tubes to the middle ear. (When you pinch the nose and swallow the first time, you should feel like your ears are closed. After this you must swallow once again without pinching the nose. This time your ears will feel like they have popped open) In addition to this, you may require nasal decongestants, mucolytics, anti allergy medications and nasal sprays to take care of the allergy, edema or mucus blockage. You will need to see an ENT specialist for a prescription. A hearing test is also indicated as barotrauma is known to affect the auditory nerve. In case you cannot avoid the flight, it is recommended that you take a nasal decongestant before you board the aircraft and suck on some lozenges during takeoff and landing. Hope this information helps you. Do let me know if you have any further questions.