There are other sources of the same story - here are some.
This one has significant discussion: https://news.ycombinator.com/item?id=9558615
Hacker told F.B.I. he made plane fly sideways
(aptn.ca)
This one also has some discussion:
https://news.ycombinator.com/item?id=9554841 Feds Say That Banned Researcher Commandeered a Plane
(wired.com)
Other submissions, there may be more:
https://news.ycombinator.com/item?id=9556690
Researcher may have adjusted airplane controls from in-flight entertainment-FBI
(theverge.com)
https://news.ycombinator.com/item?id=9558222 Security researcher claimed to hack, control plane in flight
(engadget.com)
https://news.ycombinator.com/item?id=9560248 Hacker 'made plane climb' after taking control through in-flight system
(telegraph.co.uk)
https://news.ycombinator.com/item?id=9557418 Security researcher hacks plane mid-flight
(arstechnica.com)
https://news.ycombinator.com/item?id=9557796 FBI: researcher hacked plane in-flight, causing it to "climb"
(securityaffairs.co)
https://news.ycombinator.com/item?id=9555669 Hacker told FBI he made plane fly sideways after cracking entertainment system
(aptn.ca)
https://news.ycombinator.com/item?id=9558411 Researcher hacks flight system of plane, making it climb
(dailymail.co.uk)