Question: What military branch did the president who purchased the state Yakataga Airport is located in serve?

full_context: Document 1: Reconstruction era: As Confederate states came back under control of the U.S. Army, President Abraham Lincoln set up reconstructed governments in Tennessee, Arkansas, and Louisiana during the war. He experimented by giving land to blacks in South Carolina. By fall 1865, the new President Andrew Johnson declared the war goals of national unity and the ending of slavery achieved and reconstruction completed. Republicans in Congress, refusing to accept Johnson's lenient terms, rejected new members of Congress, some of whom had been high - ranking Confederate officials a few months before. Johnson broke with the Republicans after vetoing two key bills that supported the Freedmen's Bureau and provided federal civil rights to the freedmen. The 1866 Congressional elections turned on the issue of Reconstruction, producing a sweeping Republican victory in the North, and providing the Radical Republicans with sufficient control of Congress to override Johnson's vetoes and commence their own ``Radical Reconstruction ''in 1867. That same year, Congress removed civilian governments in the South, and placed the former Confederacy under the rule of the U.S. Army. The army conducted new elections in which the freed slaves could vote, while whites who had held leading positions under the Confederacy were temporarily denied the vote and were not permitted to run for office.
Document 2: Alaska Purchase: The Alaska Purchase (Russian: Продажа Аляски, tr. Prodazha Alyaski) was the United States' acquisition of Alaska from the Russian Empire on March 30, 1867, by a treaty ratified by the United States Senate, and signed by President Andrew Johnson.
Document 3: John Aaron Rawlins: John Aaron Rawlins (February 13, 1831 September 6, 1869) was a general officer in the Union Army during the American Civil War and a cabinet officer in the Grant administration. A longtime confidant of Ulysses S. Grant, Rawlins served on Grant's staff throughout the war, rising to the rank of brevet major general, and was Grant's chief defender against allegations of insobriety. He was appointed Secretary of War when Grant was elected President of the United States.
Document 4: Flight Alaska: Flight Alaska (d/b/a Yute Air) was an American airline based in Bethel, Alaska, USA. It operated scheduled services to over 22 villages in Alaska and also provided charter services throughout Alaska. Its main base was Bethel Airport. The air carrier announced abruptly that it was ceasing operations on March 5, 2017, effective immediately, with Ravn Alaska purchasing the tangible owned assets of Yute Air and replacing Yute Air on its former routes.
Document 5: Alaska Purchase: Russia continued to see an opportunity to weaken British power by causing British Columbia, including the Royal Navy base at Esquimalt, to be surrounded or annexed by American territory. Following the Union victory in the civil war, the Tsar instructed the Russian minister to the United States, Eduard de Stoeckl, to re-enter into negotiations with William Seward in the beginning of March 1867. President Johnson was entangled in negotiations about Reconstruction and Seward had alienated a number of Republicans, so they believed that the purchase would help divert attention from the current domestic matters. The negotiations concluded after an all - night session with the signing of the treaty at 04: 00 on March 30, 1867, with the purchase price set at $7.2 million ($123 million today), or about 2 cents per acre ($4.74 / km).
Document 6: Lincoln (novel): Set during the American Civil War, the novel describes the presidency of Abraham Lincoln through the eyes of several historical figures, including presidential secretary John Hay, First Lady Mary Todd Lincoln, Secretary of State William H. Seward, Secretary of the Treasury Salmon Chase, his daughter Kate Chase, U.S. Representative Elihu B. Washburne, and conspirators John Wilkes Booth and David Herold.
Document 7: Alaska Purchase: Russia continued to see an opportunity to weaken British power by causing British Columbia, including the Royal Navy base at Esquimalt, to be surrounded or annexed by American territory. Following the Union victory in the Civil War, the Tsar instructed the Russian minister to the United States, Eduard de Stoeckl, to re-enter into negotiations with William H. Seward in the beginning of March 1867. President Johnson was entangled in negotiations about Reconstruction and Seward had alienated a number of Republicans, so they believed that the purchase would help divert attention from the domestic issues. The negotiations concluded after an all - night session with the signing of the treaty at 04: 00 on March 30, 1867, with the purchase price set at $7.2 million ($105 million in 2016), or about 2 cents per acre ($4.74 / km).
Document 8: Tuntutuliak Airport: Tuntutuliak Airport is a state-owned public-use airport located one nautical mile (1.85 km) south of the central business district of Tuntutuliak, in the Bethel Census Area of the U.S. state of Alaska.
Document 9: Yakataga Airport: Yakataga Airport is a public use airport serving Yakataga (also known as Cape Yakataga) in the U.S. state of Alaska. It is owned by Federal Aviation Administration and lies in the western section of Yakutat Borough.
Document 10: Alaska: Many communities have small air taxi services. These operations originated from the demand for customized transport to remote areas. Perhaps the most quintessentially Alaskan plane is the bush seaplane. The world's busiest seaplane base is Lake Hood, located next to Ted Stevens Anchorage International Airport, where flights bound for remote villages without an airstrip carry passengers, cargo, and many items from stores and warehouse clubs. In 2006 Alaska had the highest number of pilots per capita of any U.S. state.
Document 11: Lafayette C. Baker: Lafayette Curry Baker (October 13, 1826 – July 3, 1868) was a United States investigator and spy, serving the Union Army, during the American Civil War and under Presidents Abraham Lincoln and Andrew Johnson.
Document 12: Department of Alaska: The Department of Alaska was the designation for the government of Alaska from its purchase by the United States of America in 1867 until its organization as the District of Alaska in 1884. During the department era, Alaska was variously under the jurisdiction of the U.S. Army (until 1877), the U.S. Dept. of the Treasury (from 1877 until 1879) and the U.S. Navy (from 1879 until 1884). The area later became the District of Alaska, then the Territory of Alaska, then the State of Alaska.
Document 13: Manokotak Airport: Manokotak Airport is a state-owned public-use airport located one mile (2 km) north of the central business district of Manokotak, a city in the Dillingham Census Area of the U.S. state of Alaska.
Document 14: Alaska Purchase: The Alaska Purchase (Russian: Продажа Аляски, tr. Prodazha Alyaski) was the United States' acquisition of Alaska from the Russian Empire on March 30, 1867, by a treaty ratified by the United States Senate, and signed by president Andrew Johnson.
Document 15: Catharinus P. Buckingham: Catharinus Putnam Buckingham (March 14, 1808 – August 30, 1888) was an American soldier, college professor, author, and industrialist. He served as a general in the Union Army during the American Civil War, and was the main assistant to the U.S. Secretary of War, Edwin M. Stanton, during part of the first term of the Lincoln Administration.
ground_truth: Union Army
sub_queries: In which state is Yakataga Airport located? Answer: Alaska
who was the president when Alaska was purchased Answer: Andrew Johnson
Andrew Johnson >> military branch Answer: Union Army