Despite the high price of bottled water at the gate, it's the number one item purchased in Hudson's travel essential stores in the United States.
Hudson Group is North America's largest travel retailer, with more than 950 stores in airports and transportation terminals.
The company recently released a list of the top 10 items sold last year and there's a clear winner.
Beverages are king -- taking eight of the 10 slots.
It helps that airline liquid restrictions have turned thirsty travelers into a captive audience -- once you're past security, there's no other option than to spend.
Bottled water is not only number one, it's number one through five -- with Dasani's bottled 20 oz taking first place and Glaceau's Smartwater 23.8 oz coming in fifth.
What else do passengers want? Chocolate!
M&M Peanuts to be exact.
The only non-edible in the top 10 is "The Wall Street Journal."
Here's how it breaks down, by units sold:
1. Dasani bottled water (20 oz)
2. Glaceau Smartwater (20 oz)
3. Large Dasani (one liter)
4. Glaceau Smartwater (one liter)
5. Glaceau Smartwater (23.8 oz)
6. Diet Coke (20 oz)
7. Coca-Cola (20 oz)
8. M&M Peanut king-size
9. Coca-Cola Zero (20 oz)
10. The Wall Street Journal
The most popular newspapers were "The Wall Street Journal," followed by the "New York Post," "The New York Times" and "USA Today."
Favorite magazines were "US Weekly," "In Touch," "The Economist," "Life & Style," "Star," "Vanity Fair" and "OK."
Tina Fey's "Bossypants" topped the list of books, followed by Chris Kyle's "American Sniper" and Malcolm Gladwell's "David and Goliath."
Evolution of newsstands
Newsstands around the world have changed their model after realizing passengers want more than magazines and newspapers -- they want snacks, neck pillows and iPhone chargers, too.
Hudson News rebranded its stores in 2014 by dropping "News" from the title.
Hope Remoundos, chief marketing officer for Hudson, told Skift
in April that the intention of the name change was "to become more travel convenient" and to emphasize innovations, particularly the expansion of its electronics line.
Remoundos said they noticed "the panic on the traveler's face when their smart device had no juice, and there were only two or three plugs in the airport for somebody to plug into.
"Immediately, we added to our selection a line of chargers and [battery packs] so that all you had to do was plug in the power and you were ready to go."
Topping the list of Hudson's most expensive items sold is a pair of $1,000 ear buds -- W60 by Westone. Eight people have purchased them to date.
Mostly though, people want a bag of Lay's potato chips (number one in the snack category) and a pocket-size pack of Kleenex tissues (number one in the Health category).
They may be courting the tech-obsessed generation, but their lists show an increased demand for food.
"We attribute the demand for healthier snacks and beverages to a larger change in consumer perception about wellness, and as a result of the airlines lessening their in-flight meals and snacks," Joe DiDomizio, president & CEO of Hudson Group, told CNN.
"We've adapted by adding alternative beverage selections, such as flavored waters and more juice selections, along with yogurts, fruits and vegetables.
"We are constantly reviewing products that are gluten-free, non-GMO, whole grain, vegan and high in protein."
But the spine of Hudson and Hudson News' business still lies in books and magazines.
"Bookstores at airports and train stations are benefiting from a print revival, and this stands true for Hudson Booksellers," said DiDomizio.
This is also consistent with industry-wide trends.
In fact, the American Booksellers Association counted 1,712 member stores in 2,227 locations in 2015, up from 1,410 in 1,660 locations five years ago.
Travel retail: An estimated $60 billion business
Airports have surpassed their function as transportation centers. They're now prime commercial real estate for every travel essential and inessential: from perfumes to jewelry to fashion.
According to the Fung Business Intelligence Center, in 2014 the global travel retail market was valued at $63.5 billion. It's estimated to reach $85 billion by 2020.
Over the past 10 years, travel retail has grown at a rate of 8.4% a year.
This growth has been in tandem with the rapid increase in tourism, largely due to the democratization of affordable air travel.
According to the United Nations' World Tourism Organization, international tourist arrivals grew by 4.4% in 2015, reaching a record 1.2 billion travelers.
The most recent Moodie Report
, released last year, listed Swiss-based American-owned Dufry as the world's top travel retailer, with a 2014 turnover of around $5.4 billion.
The Hudson Group is a wholly owned subsidiary of Dufry.
In at second place was luxury retailer DFS (turnover of $4.18 billion), while South Korea's Lotte Duty Free ranked third (turnover of $3.9 billion) -- indicative of Asia being a key growth market for travel retail.