It is bound to happen almost anywhere you go. Germs are an equal opportunity invader, especially in close quarters.
Travel Tip: The better that you can build up your immunity BEFORE you travel, the more chance you will avoid nasty respiratory ailments. If you do succumb, probably you will have a much milder case, too.
May I suggest echinacea. I take a liquid form about three weeks before the start of a long trip, and continue twice a day while on the trip.
AirBourne is popular. Lavendar spray has its benefits.
Be wise, and prepare your body ahead.