It is still unclear exactly what caused EgyptAir flight MS804 to crash. So far however, intelligence officials say the confluence of data points to an act of terrorism.

There was no SoS from the pilots. The plane was out of control with no obvious signs of bad weather. Then there is the overall level of threat history of airport security lapses at all the plane’s destinations.

If terrorism was behind the crash, then many questions over airline and airport security will have to be reassessed. There also needs to be a re-examination of how information is released and relatives informed.

In the hours immediately after the plane’s disappearance from air traffic control radar, contradictory accounts from Greek and Egyptian officials suggest a less than coordinated international approach in the management of information.

This is not the first time such confusion has prevailed following airline crashes. Not only can this lead to wild and potentially incendiary speculation but exposes relatives of victims to even more emotional trauma.

Above all else, though, it is security that will come under scrutiny. In the case of Flight MS804, it was on its fifth flight of the day, having already flown from Paris to Cairo and back. It had also been to Tunisia and Eritrea. While these kinds of journeys are normal for commercial airliners, the plane’s stopovers in Tunis and Asmara mean it had been in places facing above-normal challenges in terms of terrorism and security.

It also means a large number of people had access to the aircraft in four countries including airport personnel, passengers and flight employees. And that does not even account for the checked luggage.

Security is only as strong as the weakest airport security in any chain of flight destinations. Aircraft are often not thoroughly examined at every stop.

Many developed countries already fund joint efforts to try and ensure there is security consistency across airports raising best practice at those their countries fly planes to. There are immense challenges in this however especially in dealing with certain airports in the Middle East, some African airports and others in the developing world.

That said it is also wrong to assume this is where any security lapses may have occurred in the case of flight MS804. If the flight was the target of a terrorist operation, global aviation authorities will have to confront the fact that the last line of defence against such an attack would have been at Charles de Gaulle (CDG) Airport in Paris, nominally one of the most secure facilities in Europe.

But CDG itself has been shown recently to be vulnerable to what security officials call "insider threats", where people working in secure areas may be terrorists or have been compromised by them.

After last November's Paris attacks, some airport staff had their security clearance revoked over fears of links to Islamic extremists.

Clearly more stringent screening and background checks of employees should now be implemented as part of any security overhaul.

No security precautions are entirely failsafe. But whether terrorism was or was not the cause of the EgyptAir crash, it is time to think again. Reassessing, modifying, and improving security in the face of shifting threat levels must take priority.