This happens in unpresurrised aircrafts. At landing or takeoff aircraft continue to maintain cabin pressure equals to ground pressure. So once the cabin pressure is more than the ground pressure individuals sinuses of the body come under pressure and pain take place. That time do vulsalva exercises I.e pinching nose and blowing air out of ear. This will help equalises pressure in skull and will reduce pain. Same action is of chewing gums. Mostly people who have been suffering from sinusitis do face these problems lot. So keep a nasal decongestant with you always