complaints there. now, i spoke with the tsa earlier today. i want to tell you show you what they told me. they said the tsa has a zero-tolerance for racial profiling and employs multiple checks and balances to make sure it doesn t occur. it s not only discriminatory, they say, but it s an ineffective way to identify someone intent on doing harm. the tsa says they investigated 386 complaints last year of this type. 142 of which came from this mobile app. so i ve already downloaded it just in case. samuel birk, thank you so much. and speaking of all this travel, everything you need to know, this is cool. cnn is giving you a fascinating behind the scenes look at the world s busiest airport. what we did, we sent more than three dozen of our journalists to atlanta s airport. they went on the tarmac, rode the trains, got this behind the scenes access to planes so you can check the whole thing out. go to cnn.com/atl24. coming up, a mayor handcuffed