I have to get on an airplane every week and fly from Anchorage to Prudhoe Bay, Alaska. The altitude and the difference in temperature irritate my sinuses so I often have headaches. I make sure I drink a lot of water after I get off the plane. Sometimes I take steam showers to loosen my sinuses. The best thing is my "rice sock". I took a long piece of flannel and folded it over, filled it with rice (not too full) and sewed it shut. I nuke it in the microwave for a minute or 2 then hold it over my face. The heat loosens everything up and the headache usually goes away. I try not to take too much medicine but sometimes it's the only thing that will help.

Have you heard of a neti pot? http://www.bytheplanet.com/Products/...ti/Netipot.htm
I have several friends who swear by this to help with their sinuses and allergies. I haven't tried it yet. I'm afraid it would feel like I was drowning.