No-fly list : Chris Roberts , a computer security researcher on his way to give a talk about computer security vulnerabilities at a major conference was told he could n't fly on United Airlines Saturday , due to comments he 'd made on Twitter . United Airlines stopped a prominent security researcher from boarding a California-bound flight late Saturday , following a social media post by the researcher days earlier suggesting the airline 's onboard systems could be hacked . The researcher , Chris Roberts , attempted to board a United flight from Colorado to San Francisco to speak at a major security conference there this week , but was stopped by the airline 's corporate security at the gate . Roberts founded One World Labs , which tries to discover security risks before they are exploited . Roberts had been removed from a United flight on Wednesday by the FBI after landing in Syracuse , New York , and was questioned for four hours after jokingly suggesting on Twitter he could get the oxygen masks on the plane to deploy . Authorities also seized Roberts ' laptop and other electronics , although his lawyer says he has n't seen a search warrant . A lawyer for Roberts said United gave him no detailed explanation on Saturday why he was n't allowed on the plane , saying instead the airline would be sending Roberts a letter within two weeks stating why they would n't let him fly on their aircraft . 'Given Mr. Roberts ' claims regarding manipulating aircraft systems , we 've decided it 's in the best interest of our customers and crew members that he not be allowed to fly United , ' airline spokesman Rahsaan Johnson told The Associated Press . 'However , we are confident our flight control systems could not be accessed through techniques he described . ' When asked what threat Roberts posed if United 's systems could n't be compromised , Johnson said Sunday : 'We made this decision because Mr. Roberts has made comments about having tampered with aircraft equipment , which is a violation of United policy and something customers and crews should n't have to deal with . ' Grounded : United made the decision not to allow Roberts to fly on United 'because he had made public statements about having manipulated airfare equipment and aircraft systems ' . In this Tweet , Roberts speculates on whether he should give the command to drop a 737 's oxygen masks . Hacking : Once onboard , he pondered on Twitter whether he would be able to hack into the flight 's onboard computer settings . In a previous Tweet ( seen here ) he posted pictures containing details of aircraft data . Concern : Roberts was questioned by FBI agents for four hours . All of his computer equipment , including an iPad , a MacBook Pro , several hard drives and several USB memory sticks were confiscated . Johnson said the airline reached Roberts several hours before his flight to tell him he could n't fly . But a lawyer for Roberts said Sunday that when his client received that call , the caller would only say he or she was from United , and would n't give Roberts a name or callback number . When Roberts then tried calling the number back from his phone 's caller ID , it rang instead to a resort hotel , and Roberts assumed it was a prank call , Roberts ' lawyer said . In recent weeks , Roberts gave media interviews in which he discussed airline system vulnerabilities . 'Quite simply put , we can theorize on how to turn the engines off at 35,000 feet and not have any of those damn flashing lights go off in the cockpit , ' he told Fox News . Roberts also told CNN he was able to connect to a box under his seat at least a dozen times to view data from the aircraft 's engines , fuel and flight-management systems . 'It is disappointing that United refused to allow him to board , and we hope that United learns that computer security researchers are a vital ally , not a threat , ' said Nate Cardozo , a staff attorney with the San Francisco-based Electronic Frontier Foundation , which represents Roberts . Expert ? Roberts ' talk that he was about to give was in part about the vulnerabilities of transportation systems . Blocked : United is n't happy about Chris Roberts being on its planes will no longer allow him to fly on its aircraft . Cardozo said Sunday he has n't seen a copy of a search warrant that would have been used to seize Roberts ' electronics , and that he 's working to get the devices returned . The FBI declined to comment on the matter Sunday . The Government Accountability Office said last week that some commercial aircraft may be vulnerable to hacking over their onboard wireless networks . 'Modern aircraft are increasingly connected to the Internet . This interconnectedness can potentially provide unauthorized remote access to aircraft avionics systems , ' its report found . Roberts took an alternate flight on Southwest Airlines and arrived in San Francisco Saturday evening . He speaks this week at the RSA Conference about computer security vulnerabilities .
Chris Roberts said he deleted his tweet because he 's worried that a security detail is n't being addressed . The FBI pulled him from a United Airlines Boeing 737 . Roberts said FBI agents detained and detained him for several hours . sometimes anyone can plug a laptop into the box underneath their seat and reach key details in the plane , such as engines and cabin lighting .