Airport security: How 9 11 changed flying in the U. S. | World Economic . . . In many ways, the post-9 11 scramble by airport officials to address security concerns was similar to the impulse to address public health concerns in the wake of the COVID-19 pandemic, when plastic barriers, hand sanitizers and floor markings encouraging social distancing appeared at airports throughout the U S How long the COVID-19 measures will need to stay in place remains to be seen