THE bombing of a passenger plane over the Sinai peninsula has highlighted once again that there are few better targets for the "theatre of terrorism" than an aircraft.

From the shattering of a Pan Am jet over Lockerbie in 1988 to the hijacking of the commercial airliners on September 11, terrorism and air travel have chilling association.

And yet, flying remains one of the safest modes of travel.

Depending how the figures are calculated, either air or rail travel consistently top the table for the lowest rate of fatalities.

A US study calculated that there were 0.07 fatalities for every one billion passenger miles travelled by flying, compared to 0.43 by train or 7.28 by car.

But for reluctant air travellers, there is a sense of peril and a loss of control associated with flying that no amount of rational thinking about how "you're more likely to die on the way to the airport" can ease.

Since September 11, airline passengers have walked an ever increasing gauntlet of security restrictions, from bans on liquids in hand luggage to bodyscanners capable of detecting non-metallic devices and a requirement to make sure all electronic devices are fully charged, every new measure has been designed to deter the latest innovations in extremist bomb-making.

The focus has been consistently on the passengers.

The idea that a bomb could be planted in the hold, as with the Lockerbie disaster, seemed almost retro, until Sharm el-Sheikh shifted the goalposts.

Malcolm Mathieson, managing director at aviation security specialists, Flightweight, said: "Current security measures focus predominately on just one aspect of aviation security – the screening of passengers travelling through airports to board flights and the baggage they carry.

“Unfortunately, when it comes to staff-side threats, measures are a lot more inconsistent. And this unbalanced approach – and the gaps it can create – has been shown time and time again to have the potential to severely compromise the safety of air travellers.

“A particular ongoing issue is that staff-side security measures vary considerably between jurisdictions – there’s simply no internationally agreed standard."

While UK airports screen staff every time they enter secure areas, this protocol is not mirrored everywhere - including in the US.

This has not prevented banned items ending up in the hold, however. The Herald revealed last year that around 900 dangerous goods incidents had been reported to the Civil Aviation Authority between 2009 and 2014, including one case where 200 litres of nitroglycerin ended up in the the hold of a passenger plane which had taken off from Heathrow. It was only discovered during a luggage screening on arrival at Zaghreb Airport and, while it was presumably the medicinal form of the chemical rather than the explosive, dynamite type, the fact it was loaded onto an aircraft without safety clearance or paperwork highlights the potential for very serious errors.

Prime Minister David Cameron has ordered a "rapid review" of security at a number of airports around the world in the wake of the Sinai disaster, with UK aviation experts expected to focus on the Middle East and North Africa.

It is important not to lose sight of the potential for improvement at home too.