[Veserv]

"Roberts had previously told WIRED that he caused a plane to climb during a simulated test on a virtual environment he and a colleague created, but he insisted then that he had not interfered with the operation of a plane while in flight."

So they wrote a simulation without knowing how any of it works and then showed they could hack their own cobbled together mess.

"They built a test lab using demo software obtained from infotainment vendors and others in order to explore what they could to the networks."

Yep, cobbled together random non-production infotainment software which is isolated from the actual flight systems. Generally only certified to DO-178 DAL Level D/E since they are isolated in such a way that total failure or even maliciousness can not possibly cause a meaningful safety impact.

The functional equivalent of claiming you could totally steal from a bank vault because you successfully stole some pens from the counter. Just another self-aggrandizing idiot.