Charlotte Douglas International Airport an aviation library with over 9,000 volumes and a very extensive photography collection. Rare aircraft in the collection include one of only two surviving Douglas D-558 Skystreak aircraft and the second (and oldest surviving) U.S.-built Harrier, which was used as the flight-test aircraft and accumulated over 5,000 flight-test hours. In January 2011, the museum acquired N106US, the US Airways Airbus A320 ditched by captain Chesley Sullenberger as US Airways Flight 1549 in the Hudson River on January 15, 2009. This aircraft, which was delivered on June 10, 2011, is about 35 years younger than any other commercial airliner on display
Flock (birds) to find a reliable food source will alert the flock and the entire group may benefit by this finding. While this is an obvious benefit of the information-sharing model, the cost is that the social hierarchy of the flock may result in subordinate birds being denied food by those that are dominant. Another cost is the possibility that some individuals may refuse to contribute in the search of food and instead simply wait for another member to find a food resource. These individuals are known as producers and scroungers, respectively. An intricate hunting system can be seen in the Harris's