I also never travel without Airborne. I don't know if it's mental or not, but it seems to work for me and I rarely get sick. That said, it always floors me when people who are extremely, contagiously ill choose to fly. In August I flew IAD-LAX-NRT. On the IAD-LAX flight, I was in the last row of FC. Right before landing the pilot makes an announcement requesting that everyone stay in their seats because paramedics are going to come on and take off a sick pax. I was in the last row of F and they'd moved the pax to the first row of Y, so I watched them wheel him off. Turns out the guy had chicken pox, with visible lesions and everything! How he managed to board without someone noticing is beyond me.