A 16-year-old boy will be sentenced today for sending bomb hoaxes to American Airlines and Delta Air Lines via Twitter.
The teenager, who cannot be named for legal reasons, also carried out cyber attacks around the world - including on his local police force and SeaWorld.
He targeted websites in Africa, Asia, Europe and North America from his laptop in his bedroom at home in Plympton, near Plymouth, Devon.
Devon and Cornwall Police's website was affected for 43 minutes on January 26 last year while SeaWorld suffered disruption and a loss of earnings between October 29 and November 24 in 2014.
The boy, who will appear for sentencing at Plymouth Youth Court, admitted three offences under Section 3 of the Computer Misuse Act, relating to distributed denial of service attacks (DDoS) in which a large amount of data is sent to a website.
He was convicted of two offences under Section 51 of the Criminal Law Act relating to the bomb hoaxes following a trial at Plymouth Youth Court.
The court heard he sent tweets to airlines American Airlines and Delta Air Lines - copying the White House into one - on February 13 last year.
One posted at 6.46pm to American Airlines read: "One of those lovely Boeing airplanes has a tick, tick, ticking in it. Hurry gentlemen, the clock is ticking."
Another, sent six minutes earlier to Delta Air Lines, read: "There's a nice tick, tick in one of those lovely Boeing planes, high quality."
District Judge Diane Baker warned the boy his offending passed the custody threshold when she found him guilty of the bomb hoaxes.