If you get your boarding pass on your phone, some airlines can update it if your seat or flight changes so you don't have to stand in line at a kiosk or counter.

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If they don't have a frequent-flier ID card, travelers check in online or at kiosks and get a bar code on a printed boarding pass or on a mobile phone, just like at other airlines.

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The International Air Transport Association, a worldwide travel industry group, is working on measures that will allow passengers to get their boarding passes using fingerprint or retinal scans and then pass through the checkpoint.

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When a passenger steps forward to get on a flight, an agent could hold up the boarding pass and passport in front of their smart glasses, scanning barcodes on the two documents simultaneously.

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But Precheck travelers actually don't know if they will get to use the easy screening until the TSA officer checking IDs actually scans the boarding pass.

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