I'm a believer in Airborne, but have also looked at Zicam. It appears there are different types; which are you all referring to? Might get some of that also.
On my last flight, I encountered something I hadn't seen before; the man next to me changed his baby's diaper, left it on the tray table for about 10 minutes before he excused himself to dispose of it! Had not thought about tray tables before, but will definitely be wiping it down with anti-bacterial wipe!!