Tune In Tonight: ‘Drones’ investigates unmanned aircraft inventors, pilots

“NOVA” (8 p.m., PBS) lifts the veil off our most secret weapon — just slightly. “Rise of the Drones” examines the inventors and pilots behind the unmanned aircraft that have been an essential — and largely clandestine — part of American espionage and warfare since 2001.

We meet inventor Abe Karem, known as the “Father of the Predator” drone. He spent the better part of the 1980s developing prototypes in his garage for the unmanned planes that would develop into today’s drones. He had the vision to see that the lack of a pilot and the weight of a human passenger opened up new avenues of aircraft design. His inventions were both high-tech and old-school. In one, he retrofitted an old go-kart engine to give his light, high-flying plane remarkable fuel economy.

From the era of aerial combat above the trenches of World War I to the cinematic dogfights of “Top Gun,” the emphasis has been on making jets faster and more powerful and agile. As a result, they have become hugely expensive and burn an extraordinary amount of fuel in a short time. Engineers are now working on drones that can stay aloft for days and weeks, or even longer. They’re also shrinking the size of the aircraft, enabling unforeseen access to potential foes, foreign and domestic — an ability many find troubling.

”Rise of the Drones” concentrates on the engineering, science and gadgetry of these weapons, or weaponized devices. It barely touches on the moral, legal or political consequences of their use.

“American Horror Story” (9 p.m., FX) wraps up its second season in the asylum. This year’s “Horror” has so often gone deliriously over-the-top, it’s difficult to describe. I can’t think of a more sick and disturbing TV drama ever made. And I mean that in the nicest way.

Tonight’s other highlights:

• More auditions on “American Idol” (7 p.m., Fox).

• Oliver contends with Diggle on “Arrow” (7 p.m., CW).

• Gloria’s family descends on “Modern Family” (8 p.m., ABC).

“Lords of War” (8 p.m., National Geographic) profiles collectors of military relics and memorabilia.

• Hodges is linked to a gorgeous woman on “CSI” (9 p.m., CBS).

• A record company party puts Juliette and her mother on the spot on “Nashville” (9 p.m., ABC).