Full coverage: EgyptAir Flight MS804 Missing

The disappearance of Egypt Air flight MS804 has sparked concerns about terror attacks. But before any conclusions are made, French President Francois Hollande says the country's main priority is to search for the truth, and stand in solidarity with those affected.

Families of the passengers flocked to Cairo's main airport - seeking answers. But from the start, the outlook was bleak,

MS804 had dropped off the radar just as it entered Egyptian airspace - at a height of more than 11 kilometres.

There'd been no warning from the crew that anything was wrong. Greek aviation officials said the plane made two sharp turns - before plunging into the sea.

"The last contact we had with the plan from the control tower was at about 2:30 in the morning. And after that, the plane disappeared from radar, at about 2: 50 am. There were attempts to contact the plane, but it was then confirmed that we couldn't it," Egyptian Civil Aviation minister Sherif Fathy said.

That's bound to fuel concerns that yet again terrorists have struck. And both Egypt and France have been hit before.

"And as soon as we find out the truth, we should be able to come to a conclusion. Be it an accident or another theory which each of us may be thinking, that could be a terrorist theory. But at this stage, we must first put forward our solidarity with the families, and continue to search for the cause of this catastrophe," French president Francois Hollande said.

30 of the passengers were Egyptian, 15 of them French, the remainder included people from Chad, Sudan and Algeria. A joint maritime operation is now underway to hunt for what's left of the plane.