Inside the Army’s Newest Spy Plane

From a distance, the all-white business jet parked neatly in a hangar underneath a giant American flag looks a lot like the other sleek, luxurious private planes arriving and departing from this Virginia airport. But inside, this plane is far more working class.

The cabin, full of server racks, looks more like an IT closet than an executive aircraft. The seats are cloth and two computer consoles are connected to a dozen or so antennas protruding from the plane’s belly.

To the U.S. Army, this plane—or something like it—is a...