Experts say perfect security is elusive at all airports

Explosives in the form of paper, or concealed in a medicine-sized bottle and looking like salt.
Tiny electric detonators. Security agents at the main airport in Paris are trained to detect all manner of increasingly sophisticated devices that could doom a flight.
But the chilling reality is that security is ultimately fallible.
"The infinitely perfect does not exist," said Sylvain Prevost, who trains airport personnel seeking the coveted red badge that allows them access to the airport's restricted areas.
That is especially true when 85,000 people at Charles de Gaulle airport hold red badges, which are good for three years, and many of them work for a host of private companies.

Add to the mix, concern over religious extremism in an age of increasing radicalization that can transform people within months.

Airport authorities in France and elsewhere are painfully aware of the risks, but hesitant to speculate as to whether an airport security lapse could have contributed to Thursday's crash of EgyptAir Flight 804.
The Airbus A320 took off from Charles de Gaulle with 66 people on board before lurching wildly to the left and right, spinning around and crashing into the eastern Mediterranean Sea, according to officials.
The cause of the crash remains unclear.
France has been in a state of emergency since November 13 Paris attacks that killed 130, after two deadly attacks earlier in 2015, all with links to the Islamic State group.

Security is being further reinforced ahead of the French Open tennis tournament, which starts Sunday, and the Euro 2016 soccer championships, a monthlong tournament that begins June 10.
The March 22 attacks that killed 32 people in Brussels, at the airport and in a metro station, add to the sense that public places like airports are vulnerable.
"It's possible to get any kind of dangerous object through every airport in the world due to the contradiction between time and security," said noted criminologist Alain Bauer. "Everybody wants to get in the plane fast .... So everybody compromises on time and security."

French investigators are doing background checks and interviewing ground staff at Charles de Gaulle who had a direct or indirect link to Flight 804, from baggage handlers to gate agents, a judicial official said, speaking on condition of anonymity because he was not authorized to speak publicly on the probe.