Airlines would suffer from a pandemic, but air travel might have helped cause it. Just as passenger ships brought the 1918 virus to vulnerable communities, the confined metal tubes that carry us through the skies are perfect flu incubators. We had no idea of just how big a part they played in the spread of influenza until another devastation occurred: the terrorist attacks on 9/11. There was a dramatic reduction in flights following the attacks, and a decrease in air travel persisted for some time. That year, the peak activity of the influenza virus came two weeks later than usual.
