The suspected terror attack on the terminal at Glasgow Airport today focused attention on the safety of passengers and others “landside”.
Extra security measures have already been added to the process by which passengers pass “airside” so they can board their plane and fly.
They were stepped up after fears were raised about an alleged plot to blow up planes which was said to have been thwarted last year.
But Kieran Daly, editor of online news service Air Transport Intelligence, said it was difficult to work out how much protection should be given to the terminals and approaches to them.
He said: “With landside security, there is no difference between an airport and anything else.
“It is a large building where people congregate, as they do in a nightclub.
“I would feel much more nervous about going to a club in the West End at the moment than going to Heathrow.”