Fitz John Porter
During this phase, Union Army Balloon Corps aeronaut Professor Thaddeus S. C. Lowe used two balloons, the "Constitution" and the "Intrepid", to perform aerial observation. On April 11, "Intrepid" carried Brig. Gen. Fitz John Porter, a division commander of the V Corps, aloft, but unexpected winds sent the balloon over enemy lines, causing great consternation in the Union command before other winds returned him to safety. Confederate Captain John Bryan suffered a similar wind mishap in a hot air balloon over the Yorktown lines.