United Airlines apologizes for reuse of the 9/11 flight numbers.

United briefly reinstated Airlines flight of two of the numbers that have been diverted on September 11, 2001 and are apologizing for the move.

Numbers 93 and 175 returned to probably use within recent days, apparently because of a technical error, the agency Associated Press reports.

Flight United 93 crashed in Shanksville, PA., while flight 175 flew in one of the World Trade Center towers.

Spokesman United Rahsaan Johnson said to the AP: "the company regrets the recent issues of Flight 93 and 175 use and has taken steps to remove the computer system of the airline numbers."

Blog of Time magazine wrote that one of the possible reasons for the glitch could be due to updates numbers of flight because the merger of United / Continental which was finalised in 2010.