Terrorism experts suggested that the concentration on hand luggage indicated the plot involved explosives detonated manually rather than through a remote controlled detonator or timer.
"You could carry an inert liquid that if you mix with another one could become explosive," said David Hill, a former counter-terrorism expert at the National Crime Squad and a security consultant at Red24.
"You could get the materials to make a bomb from a garden centre. Or it could be something as simple as taking on board paraffin and attempting to start a fire."
Sources told the BBC that the plot may have centred around smuggling explosives on board in fizzy drinks.
Aug 10, 2006
Beware of 'fizzy drinks'
What we're up against.