Test Pilot is a 1938 drama film starring Clark Gable, Myrna Loy, and Spencer Tracy. The film is about a daredevil test pilot, his wife, and his best friend (Wikipedia).

Rita Hayworth was an American actress and dancer. She is one of the most renowned actresses of the Golden Age of Hollywood, and was the second top pin-up girl for GIs during World War II, after Betty Grable (Wikipedia). These are the photos Brady has of Hayworth:

Bing Crosby was an American singer and actor. One of the first multimedia stars, he was one of the most popular and influential musical artists of the 20th century worldwide (Wikipedia). During World War II, Crosby made live appearances before American troops who had been fighting in the European Theater. He learned how to pronounce German from written scripts and read propaganda broadcasts intended for German forces. The nickname "Der Bingle" was common among Crosby's German listeners and came to be used by his English-speaking fans. In a poll of U.S. troops at the close of World War II, Crosby topped the list as the person who had done the most for G.I. morale, ahead of President Franklin D. Roosevelt, General Dwight Eisenhower, and comedian Bob Hope (Wikipedia, USO).

Hit the Ice is a 1943 comedy film starring comedy duo Abbott and Costello. The film is about two cameramen chased by gangsters who get jobs as waiters in small-town Idaho (Wikipedia).

Lena Horne was an American singer, actress, dancer, and civil rights activist. Horne's career spanned more than seventy years and covered film, television, and theater (Wikipedia). Horne became a fixture at the Tuskegee airbase in Alabama during World War II. There, she did everything from taking flying lessons to eating lunch with cadets to adhering to their early rising schedule. She returned to Tuskegee numerous times to boost morale, and in 1944, she served as a guest of honor at one of their graduation ceremonies (Ms. In the Biz). She also performed with the United Service Organization during the war, but eventually became disenchanted because the Army segregated her audiences and, in one instance, seated German POWs in front of Black soldiers. Horne left the USO in 1944 and financed tours of military bases herself for the remainder of the war (Wikipedia).

(You can watch a newsreel from the event pictured in the bottom left photo here [via Hearst Metrotone].)

The photo Macon has on his bunk wall of Lena Horne with a group of Tuskegee Airmen is one taken in 1945 during one of her many trips to the airbase.

The quote Crosby recites is a line spoken by Spencer Tracy in the film Test Pilot, which also starred Clark Gable.

Side note: Clark Gable enlisted in the US Army Air Forces and reportedly flew five combat missions, including one in Germany, as an observer-gunner in B-17 Flying Fortresses with the 351st Bomb Group between May and September of 1943, earning the Air Medal and the Distinguished Flying Cross for his efforts. After a mission in which his fort was heavily attacked, MGM studio executives urged the USAAF to reassign Gable to desk duty. Many of the men he served with said Gable actually unofficially joined other missions, and the aforementioned five were only a fraction of the total. He was discharged in 1947 as a major (Wikipedia, Defense Media Network).