NTO VERY useful when travelling out to the US via civilian air, but leaving the US in an RAF ac (therefore not clearing customs on departure - it can be very difficult entering the US if you didn't officially leave the last time!) Recently went to the US to pick up an RAF/BAES aircraft. Used the NTO to enter the US; no passport required, no Form I95, no fingerprints or photographs just a pleasant 'have a nice day'. Had also been informed that you could use the US residents channel with a NTO but didn't try that this time.