This is the name of the first hot-air balloon used for U.S. military purposes.
Intrepid
Constitution
Eagle
Enterprise
Enterprise. Used by for aerial observation and map-making before the First Battle of Bull Run, its success led to Thaddeus S. C. Lowe becoming the Chief Aeronaut of the Balloon Corps, which disbanded in 1863. The first balloon used during combat was the Union; it directed artillery fire at Falls Church, Va., in September 1861.