Next time you fly, take a look at the walls above the windows. You might spot black or red triangle stickers—four in total, two on each side of the plane. While they seem insignificant to most passengers, these markers are important tools for flight attendants and pilots. “If you sit in the seats marked by the triangles and look outside, you’ll notice that they line up with the airplane’s wing,” explains an aviation expert. “One points to the front and the other to the back of the wing.”

These stickers play a key role for the crew. According to Travel + Leisure, when the wings need to be inspected, pilots and flight attendants use these triangles as guides to locate the exact position. This is crucial when checking the wing’s moving parts, like the flaps and slats, for problems such as ice buildup. Without these markers, the crew would have to walk down the aisles to find the right view, making inspections much harder.

These triangles can also benefit passengers, especially those prone to motion sickness. “The wings mark the plane’s center of gravity,” says the pilot. “The plane tilts up and down around this point like a seesaw. Sitting near the wings is like sitting in the middle of the seesaw, where you feel the least movement.” For travelers sensitive to turbulence, choosing a seat near these markers can provide a smoother, more comfortable flight experience.

The usefulness of the triangle stickers goes beyond just stability. On less crowded flights, attendants from airlines like Ryanair may ask passengers to sit in seats near these stickers. This helps balance the plane. “When everyone sits closer to the center of gravity, the plane uses less fuel,” explains Captain Joe. “A well-balanced plane flies more efficiently.” A simple adjustment in seating can improve fuel economy and overall flight efficiency, proving just how vital these small markers are.

Understanding the purpose of these triangle stickers can shift your perspective on airplane seating. It’s just one of the many hidden features that contribute to a safer, more efficient flight. On your next trip, take a moment to explore other behind-the-scenes details your flight attendant may not share. You might be surprised by how much they enhance your travel experience.

Knowing these little secrets not only deepens your appreciation for air travel but also offers practical benefits, from securing a more comfortable seat to understanding the science of a balanced, fuel-efficient flight.