The flight numbers of the two hijacked planes used during September 11 attacks have been temporarily revived by the United Airlines but on Wednesday, accepted that the move was unintentional.

The call numbers 93 and 175 have been assigned by mistake to the two Continental Airlines flights which merged with the United Airlines.

Flight 175, a Boeing 767 plane departed from Boston which later on was hijacked and was one of the two planes to struck the World Trade Centre in New York.

The flight 93, a Boeing 757 plane took off from Newark International Airport, New Jersey which crashed into the Pennsylvania field. According to the investigators, the hijackers were aiming to hit either the U. S. Capitol or the White House.

The other two planes used in the attacks were of American Airlines which includes the Flight 11; a Boeing 767 plane took off from Boston and crashed into the World Trade Centre while Flight 77 from Washington Dulles which hit into the Pentagon.

According to Tnooz.com reports, the United and Continental will be using a single channel in social media mainly as @United on Twitter and the Facebook page created by United Airlines.

Jeff Smisek, the United Continental CEO, said, "What we're trying to do is bring as many of the customer benefits as early as we can".

United Continental is also hoping of getting the single operating certificate from the Federal Aviation Administration by the end of this year.