who is acting erratically, who makes them extremely nervous, someone who is exhibiting signs that other people who have executed attacks on airports and airplanes have exhibited. >> under this program, as travelers pass through airport security, a computer algorithm spots those whose travel and activities match with current threat intelligence. a human team then bets the information and if there is a red flag in the flyer's background, that person may be followed through his or her travel and watched. one attorney for the aclu saying "they are watching travelers in secret and they are doing it without any suspicion of actual wrongdoing." but it tsa official tells fox news the program has a system of checks and balances, including with the agency calls robust oversight. so the idea that ordinary u.s. citizens are being surveilled is wrong. >> average americans would not