Getting sick on vacation is like someone sitting on your birthday cake: It's disappointing, frustrating, and requires a lot of cleanup. Unfortunately, the crowded spaces travelers tend to encounter are the perfect petri dishes for illness. Cold and flu viruses spread two primary ways: when a person inhales the germs that linger in the air after a contagious person coughs or sneezes, and when someone touches a surface coated in the germs of a sick person.

With flu season looming and some of the busiest travel days of the year just ahead, we've rounded up these tips for avoiding illness while traveling.