The man, Chris Roberts, was due to fly from Colorado to San Francisco to talk at a major security conference and tweeted that he thought he could deploy the oxygen masks on board.
A man has been banned from boarding a United Airlines flight after he tweeted that he might be able to hack the aircraft's systems.
Chris Roberts, who is the founder of cybersecurity firm, One World Labs that tries to find vulnerabilities in IT systems and alert companies to them before they are exploited by criminals, was due to fly from Colorado to San Francisco to talk at a major security conference and tweeted that he thought he could deploy the oxygen masks on board.
Despite the ban, United said: "We are confident our flight control systems could not be accessed through techniques [Mr Roberts] described."
BBC reports that last Wednesday, Roberts was removed from another United flight by the FBI who took his laptop away, and questioned him for four hours.
As part of his job, Roberts had given several interviews to the media in recent weeks in which he commented on the possible weak points of airline systems.
Stating their reason for banning Roberts from the flight, United Airlines spokesman, Rahsaan Johnson said it was in the best interest of customers and crew members to not let him on the plane given his claims.
But the Electronic Frontier Foundation (EFF) which campaigns for greater openness and transparency online and represents Mr Roberts said it was disappointing that United refused to allow him to board, considering that that "computer security researchers are a vital ally, not a threat."