Flecha is the traditional name in Mexico. Elsewhere, butchers sell the same piece — or a close cousin — under a different name.
Both are short ribs cut across the bones. LA-style galbi is sliced thinner and marinated for fast tabletop grilling; flecha is cut thicker and only salted for the carne asada grill.
Same region, cut the other way: plate ribs are whole bones smoked for hours, flecha is sliced across the bones and grilled in minutes.