The Yankee Squadron was a group of mercenary American military aviators who flew for the Spanish Republican Air Force during the Spanish Civil War.

Bertrand Blanchard Acosta was a record-setting aviator and test pilot. He and Clarence D. Chamberlin set an endurance record of 51 hours, 11 minutes, and 25 seconds in the air. He later flew in the Spanish Civil War in the Yankee Squadron. He was known as the "bad boy of the air". He received numerous fines and suspensions for flying stunts such as flying under bridges or flying too close to buildings.