The apparent attempt by a passenger to blow up a US airliner in mid-Atlantic, on its flight between Paris and Miami, has added to the muddle and confusion into which the entire international air transport industry and its millions of passengers have been plunged.

The incident also poses major new questions for law-enforcement authorities around the world in their campaign against international terrorism. For the French, the incident is rightly a major embarrassment. The alleged bomber had been refused boarding for a US flight the day before. He had not, however, been detained nor his details noted. So, on Saturday, he presented himself at the American Airlines desk and was allowed onto the Miami flight. After Sept. 11, the Europeans were quick to condemn the lax security at US airports. But this major lapse of security at Paris’ Charles de Gaulle airport demonstrates that the Europeans too have some serious thinking to do about how they monitor access to aircraft.

Disturbing too for the authorities is the small but deadly quantities of explosives in the heels of the man’s shoes. Until now, the renewed security effort at airports around the world has concentrated on any sort of weapon being carried on board an aircraft in hand baggage or a passenger’s clothing. Thus pocketknives, nail files and many other normally innocuous items have been confiscated at security controls. Now, however, passengers are being required to remove their shoes to have them checked. Airlines are also becoming increasingly chary of sort of electronic equipment being brought on board their planes. If an outright ban on laptop computers is introduced, many executives, who would normally take advantage of the enforced idleness of long flights to catch up with their work, will think twice about traveling. The explosive growth of e-mail and the rapidly improving quality of videophoning will encourage them to stay in their offices and have their meetings telephonically. Airlines will, therefore take a further financial hit in the one area, executive travel, from which they have traditionally earned the biggest part of their income.

There is as yet no firmly proven link between the suspect and the Al-Qaeda network, but leaks from the FBI suggest that the man they are holding was certainly not working alone. He is apparently a small-time British crook of small intelligence. The way in which he tried to set fire to the explosives while in his seat would seem to bear this out. Had he gone to a lavatory to ignite them, the results for the American Airlines flight and its 200 passengers could have been tragically different.

If the man does turn out to be another Al-Qaeda suicide bomber, it will also pose a large question about the competence of the British security operatives. Given the vastly heightened state of alert since Sept. 11 and the draconian security laws introduced by the Blair government, it can be wondered what on earth British intelligence has been doing for the last three months. Until hugely expensive new explosives-sniffing equipment can be installed at airports around the world, it seems that airline passengers will have to endure ever more stringent and annoying security checks, before they are allowed near their flight.