ourplnt.com
A replica of a Pelagornis skeleton at the National Museum of Natural History - Our Planet
The largest known flight-capable bird was Pelagornis sandersi, discovered in 1983 in Charleston, South Carolina, during construction for a new airport terminal. It lived 50 million years ago. The largest specimen found in Antarctica, and its wings, fully extended, spanned more than 6.4 meters (21 feet). Pelagornis sandersi probably weighed between 48.5 and 88 lb (22 and 40 kilograms). Photo: A replica of a Pelagornis skeleton at the National Museum of Natural History (wikipedia).