them. >> reporter: not necessarily. while the u.s. department of transportation prohibits airlines from keeping passengers on a plane for more than four hours leaving from the u.s. those rules do not apply to foreign carriers overseas. >> if it had happened in san francisco, they would have off the airline within a matter of hours, three to four hours. at the other end of this flight there are no regulations there. they give people a chance to get off the plane. >> so that same fog delay kept another flight on the ground even longer, talking about 13 hours. it was diverted after an older passenger died aboard the flight. the airline released a statement confirming the ordeal saying flight passengers were informed about the need for a medical diversion involving a 73-year-old male passenger, we apologize to those passengers affected by these delays which were beyond the airline's control and offers its deepest