According to the old saying, you can choose your friends but you can't choose your relatives. And unless you're traveling with a plane full of friends, you also can't choose who's sitting in the seats around you.
Many people who get sick after a plane trip blame recycled "cabin air." But Humana, the big health insurer, says cabin air is not the culprit. It's usually a person coughing or sneezing who is spreading the germs. Humana says you should tactfully ask coughers and sneezers to cover their faces with a tissue. If confrontation makes you uncomfortable, consider wearing a face mask.
And be wary of the washroom. Germs are spread by moisture, so airplane lavatories are breeding grounds. To lower the odds of getting sick, Humana says slather on the hand sanitizer available in most airplane bathrooms, or, better yet, keep a small container in your carry-on bag.