On March 11, 1957, US-American explorer and aviator Richard Evelyn Byrd Jr. passed away. He claimed to be the first man to fly over both of the Earth’s poles.
Richard Evelyn Byrd was born in 1888 and entered the United States Navy Academy at the age of 20. It is assumed that his passion for aviation evolved during World War I when he learned how to fly. Soon, Byrd became a flight instructor for the US Navy. Due to Byrd’s expertise in aerial navigation, the aviator was appointed to plan the flight path for the U.S. Navy’s 1919 transatlantic crossing. He then commanded the aviation unit of the arctic expedition to North Greenland led by Donald B. MacMillan from June to October 1925. 
In 1926, Richard Byrd and pilot Floyd Bennett attempted a flight over the North Pole in a Fokker F-VII Tri-motor monoplane called Josephine Ford. The crew took off at Spitsbergen and covered about 1.360 miles in less than 16 hours. The pilots claimed to have reached the North Pole and Byrd received the Medal of Honor for his achievement. Also, his claims enabled him to secure fundings for an attempt to fly over the South Pole. However, with the years, heated controversies evolved about whether the pilots were actually able to reach the North Pole. Most of the critics brought to attention that the Josephine Ford may not have had enugh speed and winds to accomplish a flight from Spitzbergen to the North Pole and back in less than 16 hours. Since then, many publications try to reveal the truth around Byrd’s flight, but there are still open questions. [2,3] Further explorers claiming to have made the first successful expedition to the North Pole were Robert E. Peary  and Frederick Cook.
One year after the controversal flight, Richard Byrd announced to have the financial backings to attempt to win the Orteig Prize for making the first nonstop flight between the United States and France. He announced Floyd Bennett again as his chief pilot. However, during a practice, the Fokker Trimotor airplane crashed, injuring Bennett and Byrd. While the plane was going through repairs, Charles Lindbergh won the prestigous prize on May 21, 1927. 
In 1928, Richard Byrd set himself another goal. He wanted to reach the South Pole by flight. With the expedition that consisted of two ships and three planes he established base camp called “Little America” on Ross Ice Shelf, from which many foot, sled and airplane expeditions were launched. The famous South Polar flight took place on November 28, 1929. To avoid the same mistakes he did during previous expeditions, Byrd paid special attention to data collection. Despite several difficulties during the adventure, Richard Byrd’s expedition was probably the first to reach the South Pole by air. Due to his success, Byrd took part in four more Antarctic expeditions and he managed to survive 5 winters alone while operating a meteorological station. 
At yovisto academic video search, you can watch a movie by Admiral Peary’s adversary Dr. Frederick Cook in 1912, produced to substantiate his claim as discoverer of the North Pole.
References and Further Reading:
-  Richard E. Byrd at the South Pole Website
-  An Overview of the Controversy of The North Pole Flight of Richard E. Byrd
-  Richard E. Byrd and the North Pole Flight of 1926 – Fact, Fiction and Interpretation
-  Richard E. Byrd at Famous Explorers
-  Robert E. Peary’s Arctic Expedition, SciHi Blog, February 20, 2015
-  Robert E. Peary at Wikidata