How about this idea: Much of the congestion is caused by people stowing their bags overhead further down the plane than their seat, then having to reverse agai

How about this idea: Much of the congestion is caused by people stowing their bags overhead further down the plane than their seat, then having to reverse against traffic for X rows to sit down. Also there is a large fixed time cost once the overhead bins fill up and X passengers are forced to check their bags; they have to haul them all the way to the front against traffic. What if a system was installed at the security checkpoint that recorded whether a passenger were boarding with a suitcase, and then assigned them a bin overhead. The bins would have small LED screens that displayed the passenger's name or seat number. An algorithm would match the bins to the nearest seats, and reduce or possibly eliminate downstream luggage-stowing. It would also be able to tell passengers that they were too late, the bins were full, and they would have to check their bags. Difficulties -- * some bags are small or irregular, can fit 2 in a bin (measure bag during X-ray?) * initially people won't understand the system leading to chaos