A security researcher's tweet proved him taxing as he was not allowed to board a California-bound flight on Saturday. The researcher, Chris Roberts, has posted a social media post some day earlier in which he said that the airline's onboard system could be hacked.

Roberts tried boarding a United Airlines flight to San Francisco where he had to take part in a security conference, but was stopped by airline security. Roberts was taken off from the flight by the FBI after it landed in Syracuse, NY.

He was then questioned for hours about the joke and they have even sized Roberts' electronics. Roberts' lawyer said no search warrant has been issued against him. The lawyers said when the airlines took Roberts off the plane, they did not provide a proper explanation of doing so.

They said the airline would send Roberts a letter in next two weeks in which the reason would be explained. "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", affirmed airline spokesman Rahsaan Johnson.

It was asked that what threat Roberts posed when United's systems cannot be compromised, Johnson said it was with regard to his comments about tampering with the airline and that is a violation. Johnson also told that the airline contacted him hours before revealing he could not fly. But the lawyer said that Roberts thought that the call was just a prank.

Lately, Roberts has also spoken about airline system weaknesses. Many times, Roberts has fixed a box under his seat to view data from the aircraft's engines, fuel and flight-management systems.