Starting September 1st, some travelers will begin providing their birth date and sex when booking their airline reservations.

It's the second part of the government's phased-in program, Secure Flight, to match passengers' names against the government's terrorism watch list. Earlier in the summer, when passengers booked their online travel they had to provide the airline with exactly how their name appears on their government-issued identification card—whether it be a driver's license or a passport.