Whenever we go on trips, this is what I do- but, I'm also crazy...
Week before trip- probiotic yogurt every day, take multi-vitamin every day
Evening before flight- airborn
Morning of flight- airborn
Onflight- NEVER touch face or eat anything without using hand sanitizer first
Once we get in the hotel room- put tv remote in plastic bag, disinfect ALL surfaces with Lysol Wipes (including phone, door knobs, counters, EVERYTHING)
Continue using hand sanitizer before eating or touching face every day, continue taking multi-vitamin
Night before flight- airborn
Morning of flight- airborn
This keeps me and DH healthy when we go on trips. You also want to make sure that you drink LOTS of water, and even use nasal spray, or put petrol. jelly up your nose before the flight to make sure the inside of your nose is 'moist'. The dry nasal passages are a haven for germs circulated in the airplane cabin.
There's my 2 cents. I do that ANY time of year