Washington ? The safety net tightened around air travel Friday as British flights to Washington and Riyadh, Saudi Arabia, were canceled, while law enforcement officials acknowledged that some delays were caused by mistaken identities. Mexican authorities also reported another cancellation.

British Airways said a flight to Riyadh, which had been due to leave London’s Heathrow Airport today, was scrapped along with a return flight scheduled to leave Riyadh on Sunday.

The airline also canceled its third flight in 24 hours Friday between London and Washington’s Dulles International Airport, and another flight from London arrived at Dulles two hours late on Friday because of additional passenger screening.

The British carrier wasn’t the only airline canceling flights in recent days. A second Aeromexico flight from Mexico City to Los Angeles was canceled because of U.S. concerns that it was a terrorism risk, airline and Mexican government officials reported Friday.

The flight had been scheduled to take off at 6:55 p.m. Thursday but was canceled by Mexican civil aviation authorities, Aeromexico reported. An Aeromexico flight with the same number was canceled Wednesday.

Thursday’s flight was canceled after U.S officials said they were concerned it might be a safety risk, said Agustin Gutierrez, a spokesman for President Vicente Fox.

Sen. Jay Rockefeller, D-W.Va., senior Democrat on the Senate Intelligence Committee, said officials were getting “an enormous amount of much more than single-source reporting that is very specific.” The information can come from computerized watch lists, interception of communications and intelligence agents, he said.

Mistakes are inevitable, Rockefeller said, but the failure to respond “is a far worse alternative in spite of the inconvenience to passengers.”

A police officer patrols in front of an Air France plane bound for Los Angeles at Charles de Gaulle airport, north of Paris. Air France canceled up to six flights between Paris and Los Angeles over in the Christmas holiday after security discussions between U.S. and French officials. French police confirmed Friday that six cases of mistaken identity, not terrorists, were behind the pre-Christmas emergency grounding of the flights.