The small black or red triangles found above certain windows in an airplane cabin are known as "William's Seats" or "the best view in the house." They mark the windows that offer the most direct and clearest view of the aircraft's wings. These markers are primarily for the flight crew's benefit during an emergency or a suspected mechanical issue. If a pilot needs to visually check the status of the flaps, slats, or engines, or if they need to verify if there is ice buildup on the wing, they don't have time to guess which window is best; they simply look for the triangle. In the event of a landing gear issue, the crew can also use these windows to see if the gear has properly deployed. For passengers, sitting in a "triangle seat" is a fun "av-geek" perk, as it provides the most symmetrical and unobstructed view of the wing's movement during takeoff and landing. In 2026, these stickers remain a standard safety feature on almost all Airbus and Boeing commercial aircraft, serving as a low-tech but essential diagnostic tool for the crew.