Quetzalcoatlus northropi was one of the largest flying animals ever to exist—and it completely rewrites what we think is possible in vertebrate flight. Living ~68–66 million years ago (Late Cretaceous), this azhdarchid pterosaur had an estimated wingspan of 10–11 meters (33–36 ft)—comparable to a small airplane. Despite that size, its bones were pneumatized (air-filled), giving it an extreme strength-to-weight ratio optimized for flight. Unlike birds, pterosaurs flew using a membrane wing supported by an elongated fourth finger. In Quetzalcoatlus, the wing membrane likely extended to the hind limbs, forming a large lifting surface with high glide efficiency—ideal for dynamic soaring and long-distance travel. Biomechanical modeling suggests it used a quadrupedal launch: pushing off the ground with all four limbs in a powerful vault, rather than a bird-like hindlimb jump. This launch method may be the key adaptation that allowed such massive animals to get airborne. On land, evidence...