Security researchers found that in less than 60 seconds, they could open a hatch on a plane’s exterior, plug in a tiny device, and redirect the aircraft’s autopilot or sabotage its flight plan.

Photo-Illustration: Jobanny Cabrera; Getty Images

Even as the digital components of so many life-critical systems have proven susceptible to cybersabotage— cars , medical devices , even water utilities and power grids —the computer systems of airplanes have, thankfully, remained uniquely inaccessible to hackers. But one group of academic researchers has spent years testing a different, devious approach to aviation cybersecurity.…