I have horrible, horrible sinus issues. Plane rides can be a nightmare. I use Earplanes, which help *somewhat.* I still have ear and jaw pain when I fly, but the pain doesn't last as long with the Earplanes. Sometimes after landing, my ears are OK when I wear the Earplanes, and I consider that to be a near miracle!
I wear the Earplanes for a whole flight, putting them in before take-off and taking them out after the doors to the plane are opened at landing. If you're going to use them for only part of a flight, landing time is usually more brutal than take-off. Put them in before the plane starts to descend to land.
I also chew gum or use a lollipop, and I swallow a lot of water during the flight. During landing time, I guzzle down the water! I also start taking Sudafed around the clock about 48 hours before each flight.
One more thing I do is use a nasal spray about 30 minutes before take-off. My doctor said that overall nasal sprays are not good, but for flying they are OK to use. I use them only when I fly. Remember that they are a liquid and must go in your "liquid baggie" at the security check if you bring a nasal spray on the plane.