Carol
It's the germs that are being recycled on airplanes that make you sick. Before flying, put a little bit of vaseline in each nostil so the germs will not adhere to the nose hairs. Also, turn off the air above your seat, and wipe off the eating tray with an antibacterial wipe before using. Finally, wash your hands as soon as you deboard the plane. This is advice from my son's pediatrician, and it worked for us on our last trip.