LM Otero, Associated Press
In this Nov. 13, 2014 photo, a Southwest Airlines pilot and co-pilot work in the cockpit on an early morning originator flight that waiting for departure from Love Field in Dallas. Europe's aviation safety agency recommended Friday that airlines always have two people in the cockpit of a flying aircraft after it emerged that the co-pilot of Germanwings Flight 9525 had apparently locked himself in the cockpit to crash the plane.

COPENHAGEN, Denmark — Europe's aviation safety agency recommended Friday that airlines always have two people in the cockpit of a flying aircraft after it emerged that the co-pilot of Germanwings Flight 9525 had apparently locked himself in the cockpit to crash the plane.

European airlines, including the Lufthansa Group that includes Germanwings, were already committing to impose the measure as soon as possible.

EASA Executive Director Patrick Ky said that "while we are still mourning the victims, all our efforts focus on improving the safety and security of passengers and crews."

Before the official recommendation, Lufthansa said it would move to the two-person rule "as soon as possible" across its airlines, which besides Germanwings also includes Austrian Airlines and Swiss Air.

German airline Germania, Hungary-based low-cost airline Wizz Air and Belgian tour operator Thomas Cook said Friday they had adopted the policy.

On Thursday, EasyJet and Europe's third largest budget airline, Norwegian Air Shuttle, had said they would adopt the rule. Air Canada said the same.

Following the Sept. 11, 2001 terrorist attacks, U.S. airlines revamped their policies regarding staffing in the cockpit. But the procedure is not standard in Europe or Canada.

The president of the German pilots union Cockpit told AP that his organization would support measures requiring airlines to have two people in the cockpit at all times during the flight, but cautioned that such a move wouldn't necessarily solve all security problems.

"We would appreciate a swift decision in order to restore confidence in air travel," Ilja Schulz told The Associated Press. "It's fine as an intermediate measure but once this investigation has been completed, all sides need to sit down and examine what measures can improve security without causing new problems."

Experts say that one security rule is to keep the door shut as much as possible, something which a two-person rule would not necessarily encourage. Also, replacement staff might not have had the same medical and psychological checks.

Denmark's Transport Minister Magnus Heunicke that the Danish Transport Authority also would review all physical and mental tests of pilots flying to and from Denmark. German news media have depicted co-pilot Andreas Lubitz as a man with a history of depression who had received psychological treatment.

Raf Casert reported from Brussels. Pablo Gorondi in Budapest, Ciaran Giles in Madrid and Frank Jordans in Berlin contributed to this report.