| United States Army Border Air Patrol | |
|---|---|
 12th Aero Squadron Dayton-Wright DH-4 flying liaison with US Cavalry on United States/Mexico border patrol | |
| Active | June 1919 – July 1921 |
| Country |  United States of America |
| Branch |  United States Army |
| Type | Air force |
| Role | Aerial warfare |
| Size | By mid-September 1919 the force was 104 officers, 491 enlisted men, and 67 planes |
| Engagements | |
| Commanders | |
| Notable commanders | Lt. Col. Henry B. Clagett |
With the end of World War I in 1918, the Air Service, United States Army was largely demobilized. During the demobilization period of 1919, the Regular Army and its air arm answered a call to defend the southern border against raids from Mexico, and to halt smuggling of illegal aliens and narcotics into the United States and weapons from the United States into Mexico.