busiest airports a little later and give an update on what is happening with the passengers and the flights as we get those developments. new report raising alarms about air security. international flights that pass above us without stopping in the states could have dangerous cargo, and we would never know it, they are saying, until it's too late. national correspondent catherine herridge has to story. >> reporter: a former senior tsa official tells fox the vast majority of the over flights come from canada and the u.s. government has confidence in the canadian screening system. that said the security in place today for all aircraft is dictated by the 9/11 act that was based on the recommendations of the 9/11 commission and the law does not include cargo on over flights. for some context the department of homeland security uses what they describe as a risk-based approach, which means you can't protect everything all of the time and over flights are a lower priority than domestic passenger flights.