The US Air Force turns 75 on September 18, the date when the Air Force formally separated from the US Army under the terms of the National Security Act of 1947. But if you really want to trace the origins of America’s air power, you need to go back to the Civil War and an eccentric man obsessed with hydrogen balloons.

The “Father of the US Air Force” was General Henry “Hap” Arnold, the man who steered the branch to its emancipation from the US Army on September 18, 1947.

But if Hap Arnold, who was taught to fly by the Wright brothers, was the USAF’s father, then who was its grandfather?

Let me introduce you to Thaddeus Sobieski Constantine Lowe, the eccentric founder of “Thaddeus Lowe’s Aeronautical Corps.”

Thaddeus Lowe became obsessed with lighter-than-air gases as a child and had devoted his life to balloon aviation by age 18. He wasn’t really a professor—he was more like a carnival showman. He barnstormed the country with his fleet of giant balloons and plotted the world’s first flight across the Atlantic Ocean.

A test flight from Cincinnati to Washington, D.C. went badly off course in April 1861. Professor Lowe landed in South Carolina, whose forces had just fired upon Union soldiers at Fort Sumpter, triggering the Civil War. Seized as a suspected Union spy, Lowe returned North after convincing his captors he was a mere man of science.

The episode caught the attention of President Abraham Lincoln, who summoned Lowe to Washington for a demonstration of the military potential of airships. Lincoln stood agog on the National Mall as Lowe rose to 500 feet with a copper wire dangling to the ground. Lowe tapped out a message from the balloon’s gondola:

I have pleasure in sending you this first dispatch ever telegraphed from an aerial station.

Lincoln, our only President with a patent, loved technology more than any Commander-in-Chief, save maybe Jefferson. He immediately saw the tactical value of Lowe’s balloon. The President turned to his Army commander, General Winfield Scott, and introduced Professor Lowe as his new “Chief Aeronaut.”

The Union Army Balloon Corps was born.

Lowe was there with his team of recruits, his hydrogen gas generators, and growing fleet of double-ply India silk “pongee” balloons for the First Battle of Bull Run and the Peninsula Campaign, as well as Fredericksburg and Chancellorsville. His job was to observe and report on Confederate troop movements and track the accuracy of artillery fire.

The Balloon Corps’ success was evidenced in the fire Lowe endured from Confederate ground troops trying to avoid detection. The rebels would eventually innovate disguising tactics we take for granted today: camouflage, blackouts, and the creation of dummy armies, including “Quaker guns,” timbers painted black to look like cannons from above.

The Confederates floated their own balloon experiments, but the materials shortage hampered their efforts. One attempt consisted of silk ballgowns sewn together and sent aloft with flaming oil-soaked pinecones.

Lowe, suffering from malaria caught in the Peninsula Campaign, quit the Balloon Corps in the spring of 1863 over accusations of financial impropriety and maladministration. Army brass didn’t like his swashbuckling style, and he bristled at attempts to rein in his activities.

Lowe would go on to make millions on his patents for ice making and hydrogen gas production, the latter revolutionizing home heating.

The Balloon Corps would re-emerge in the Spanish-American War as the Balloon Detachment, Signal Corps. A Lowe-designed airship named the Santiago would serve in the Battle of San Juan Hill in Cuba in July 1898.

Then, in 1907, the Army Signal Corps created the Aeronautical Division, initially conceived as a fleet of dirigibles. The following year, the Division purchased a Wright Model A from the Wright brothers. It crashed on a test flight, killing the only experienced military aviator, Lieutenant Thomas Selfridge.

But neither the Wright Brothers nor the Signal Corps would be deterred.

In 1911, twenty-five-year-old infantry Lt. Henry Arnold requested a transfer to the Signal Corps, specifically, to the Wright Brothers’ Aviation School in Dayton, Ohio. Arnold climbed behind the controls of the Wright Model B for the first time on May 3.

The rest is history.