What price security in the air?
Airport security is exasperating enough without tightened restrictions, so a pause for reflection and expert advice is in order before action to tackle the threat of cargo bombs. But those opposing heightened measures, or demanding a relaxation of passenger security, might pause too.
Only last week, British Airways chairman Martin Broughton declared elements of airport security "redundant", an intervention we can put down to concern for the passenger experience and perhaps poor timing. Neither could apply to Ryanair boss Michael O'Leary who this week denounced "a lurch into making travel even more uncomfortable" - a job he sees as his own.
The last time someone smuggled a bomb into the cargo of a passenger aircraft it brought down a Boeing 747, killing 270 people. The legacy of the 1988 Lockerbie bomb remains with us - the cargo security measures in force up to last week date from that time. The carrier involved, Pan Am, never recovered and folded three years later.
So exasperation or not, the bomb discoveries threaten rather worse if nothing is done.
Each of the devices built into desktop computer printers found at East Midlands airport and Dubai contained enough PETN plastic explosive to down an aircraft and at least one had been carried on a passenger flight.
In reality, it was only a matter of time before this happened. One third of world trade goods are distributed by air and almost two thirds of UK air freight is carried on passenger aircraft. We are entitled to ask why nothing was done to tighten security before.
PETN is a common explosive, used by the shoe bomber who tried to bring down a transatlantic flight from Paris in December 2001 - the reason passengers must often remove their shoes at airport security. It is not difficult to detect chemically, but hidden in a cargo package PETN is highly expensive and time-consuming to spot. That is the problem.
A recent US requirement to screen all cargo on passenger aircraft will cost £436 million to introduce. It will raise the price of goods, no doubt produce a shift in freight to shipping and cut the income of carriers unless they raise fares for passengers.
It's worth noting that much air cargo comprises electronic goods, engineering and machine parts, scrap metal and cars. Why? I understand the need to shift fruit and vegetables by air - although why apples must be flown from New Zealand during the British apple harvest escapes me. But what is wrong with shipping everything non-perishable on environmental as well as security grounds?
The reality is there is an arms race between airport security and would-be bombers, and no prospect of detente. The industry has to deal with it.
At the time of Lockerbie it was argued screening passenger baggage would pose huge problems. It does not appear to have hindered growth in air travel. The restriction on liquids in carry-on bags, introduced in 2006, is a nuisance. But how much of a hardship compared to exploding at 36,000 feet?
There is inconsistency between - and even within - airports, but if that is frustrating, some of it also serves a purpose. Take the removal of shoes. At present, UK airports request a proportion of passengers take off shoes in lieu of asking everyone. If it was clear what that proportion was, prospective shoe bombers could keep count and assess the odds of keeping their boots on. Uncertainty is itself a security measure.
And in truth, how bad is the experience? I have flown from Heathrow several times recently and been detained at security no more than 10 minutes. Passport control on flying into the airport is another story. On a recent Sunday night it would have been quicker to fly to Manchester and take a train back to London - while God help those without an EU passport.
What on earth will World Travel Market visitors, arriving this weekend, make of the world's longest passport queues?