Why do flight attendants secretly dread your Diet Coke request?
Next time you fly, you might have to rethink ordering a Diet Coke from the drink cart
Picture yourself nestled into a cramped window seat at 35,000 feet, your throat parched from the bone-dry cabin air. When the refreshment cart finally rolls down the aisle, you eagerly ask the attendant for a crisp, refreshing Diet Coke. It feels like a harmless request. However, as the cabin crew member cracks open the silver can, a wave of frustration washes over them. While you see it as just a midday pick-me-up, for the crew, it tests their patience, as they recently shared their feelings about this in an article published by Travel+Leisure on July 14, 2026.
An operational headache
For the cabin crew, a seemingly harmless beverage translates into an operational headache. Pouring Diet Coke is known to be one of the biggest slowdowns for flight attendants during service. "People ordering Diet Coke in the air is one of the most frustrating experiences as a flight attendant," explains Luke Gary, a flight attendant. He notes that it takes about a minute for the bubbles to fizzle out before the attendants can fill a cup one-fourth full. After that, they must continue pouring the drink while engaging in brief small talk with the passenger since no one likes an awkward silence. As we know already, small talk is hard in itself. To add a mandatory lag into it, while other passengers beckon their attention, sounds genuinely tiresome. However, the hospitality industry hinges on the 'smooth' and 'likeable' personalities of its customer-facing staff.
Pressure problems
The root cause of this pour-and-pause traces back to the moment the cabin seals and the aircraft climbs to its cruising altitude. Because the cabins are artificially pressurized to mirror high-altitude atmospheric conditions, the ambient air pressure drops significantly compared to the ground. This drop in external pressure means that dissolved carbon dioxide inside the soft drinks is eager to escape into a massive layer of froth, turning a simple task of pouring it into a cup into a waiting game.
The diet soda nightmare
While this happens with all the carbonated beverages, the diet sodas stand out as the ultimate time waster. The reason for this is the artificial sweeteners that drinks such as Diet Coke contain. Sweeteners like aspartame lower the surface tension far more than high-fructose corn syrup or sugar found in regular sodas. Additionally, the diet version has a higher physical viscosity, which acts as a stabilizer for escaping carbon dioxide. As a result, the bubbles don't just form aggressively; they linger, creating a thick, stubborn blanket of foam that refuses to dissipate.
The viral sky trick
To combat this altitude anomaly, flight attendants have taken to social media to showcase a clever gravity trick that bypasses the foam altogether. Instead of a traditional pour, the veteran attendants flip the plastic cup upside down directly over the open mouth of the can, then swiftly invert both together. By lifting the can slowly and letting the air pressure control the flow, the liquid transfers into the cup with almost zero turbulence. For crews rushing to serve hundreds of passengers before descent, mastering this is perhaps the only way.
Soft drinks reign supreme
Despite the discomfort it might bring to the flight attendants, people prioritize soft drinks, juice, and water over alcohol. According to a study published by the Journal of Travel Medicine, a majority of passengers, or 84% to be precise, don't intend to consume alcohol on a flight. Instead, they tend to prefer other drinks such as soft drinks. Nonetheless, out of the 16% who did plan to order a drink, 89% confirmed that they would limit themselves to about one or two drinks maximum.
Just hand them a whole can
That said, people in the comment section of a post by Travel+Leisure (@travelandleisure) had their own views regarding the matter. @santa_j_claus wrote, "Or just hand them the whole can and ask if they would like a cup of ice." At the same time, @charlyontv argued, "No FA is trying to make conversation with each passenger while pouring their drinks. Regardless, I’ll take the whole can. Thank you!"
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