And, with airport security at an all-time high, Transportation Security Administration (TSA) officials gather mounds and mounds of surrendered items each year, from lotions and perfumes to knives, bats and more.
So what happens to the contents of that suitcase left behind? Just who profits from the more than seven million items left behind at airports across the country each year?
The answer, it turns out, could be you!
"Good Morning America" discovered the millions of dollars worth of merchandise left behind at airports each year is available to the public, at a huge discount.
Items left behind at airports are delivered to local surplus stores, where everyday Americans can buy them for a huge discount, often as much as 70 percent. Some states also post the deals online, meaning you don't even have to leave your home to rake in the savings.
A "GMA" tour of a surplus store in Austin, Texas, for example, found designer sunglasses that regularly sell for $300 on sale for $50. And a set a Tiffany's earrings that would retail for around $4,500 were estimated to go on sale at the surplus store for between $750 and $1,000.
Austin resident Rebecca Huffman is one smart shopper taking advantage of the deals by shopping at surplus stores weekly, and then reselling the items herself on online retail sites like eBay.
"I clear about $1,000 a month and, around Christmas, about $2,000 a month," Huffman told "GMA."
The deal-making is a win-win situation for states too. The money made in each state's surplus stores and online sales goes right back to the state's coffers.
"Since 2004, when we began participating in the program, we have brought over $700,000 back into the state," Troy Thompson of the Pennsylvania Department of General Services, told "GMA."
How can you cash in?
Visit these sites to learn more: