More than 211 million Americans are expected to fly this summer, and if you're one of them, you could be a target of airport theft.
You may be in the sights of thieves -- usually fellow passengers who see the opportunity to get something for nothing.
"Good Morning America" discovered alarming surveillance tapes that show it happening. For example, one surveillance video from the Phoenix airport shows a woman reaching into someone else's bin, picking up a cell phone, covering it up with her sweater and walking away.
Another tape from the same airport shows a man in a red shirt and cowboy hat swiping an $800 watch from the conveyor belt, while Jason Haase, the watch's owner, was undergoes additional screening.
"It was a very nice watch. … I figured it was gone for good," said Haase.
In another incident a traveler at Chicago's busy O'Hare Airport puts his laptop on a chair. Another guy spots the computer, sits on it then stuffs it away for himself.
Gina Preston became a victim after she set off the metal detector at an airport checkpoint.
"I said 'oh must be my phone.' I walked back, slid it into the last bin I had, walked through the metal detector, got my stuff at the other end … and [found] no phone," Preston said.
Preston says police told her the thief was the guy behind her in line, but they couldn't identify him.
Steven Frischling is a professional photographer who travels 200,000 miles a year taking pictures. He runs a Web site for frequent fliers. "I've actually spoken with airport thieves," he said.
Frischling suggests putting loose items like your keys, phone, jewelry and coins in a zipped jacket pocket or bag, instead of loose in a bin. "No one can steal it. No one can reach into my jacket and take my items," he said.
Frischling also recommends putting your belongings through the scanner in a specific order.
"I make sure my shoes and my jacket are the first items in the bin in the X-ray machine. … That's so when they go through I can grab my jacket and put my shoes back on," he said.
His laptop is always second so it's book-ended by his other belongings, because he says it "is the most vulnerable to being stolen on the other end."
The item you're least worried about goes last. "If it gets stopped I can keep an eye on everything else from the metal detector," he explained.
If something gets stolen, the key is to report it right away.
"In instances when we've had thefts reported to us we've had a very good record of recovering the property. When there is a time lapse it drops dramatically," said Phoenix Airport policeman Lt. Rick Gehlbach.
"Since TSA [Transportation Security Administration] has closed circuit TV at most checkpoints, we're seeing less and less theft," said the agency's Ellen Howe. But TSA has no specific statistics to back that up, because the agency lumps checkpoint thefts together with all other reports of lost or stolen belongings.
Sometimes, you have to get lucky though. After Jason Haase's watch was stolen, while he was waiting for his flight, he spotted the guy in the cowboy hat and confronted him.
"I said, 'We can handle this two ways.' I said, 'You can give me my watch back and I can catch my plane, or you're going to jail,'" said Haase. He got the watch back and made his flight.
There are no good national numbers for checkpoint theft. The TSA lumps those claims together with "other" reports of lost and stolen property.