On reddit, /u/Otherwise_Finger_166 asks what this symbol means. One joker suggests, "This side up," but the black triangle actually designates an important location called William Shatner's Seat.
The New York Post explains that it is from this location that aircraft crew can get the best view of the wing and thereby assess its condition. The presence of ice could necessitate a change of plans.
Why is it named after William Shatner? Before Star Trek, Shatner starred in a 1963 episode of The Twilight Zone titled "Nightmare at 20,000 Feet." Shatner is an aircraft passenger sitting over the wing who sees a creature tearing up the plane. Prudent aircraft designers have clearly learned from that episode how important it is to get the best view of the wings.
-via Massimo
