Travellers and transportation screeners alike dream of a day when people will no longer have to spread their legs and lift their arms for intimate pat-downs or see-through body scanners.

Laptops would never have to be taken out of bags, shoes would stay snugly on the feet and yet danger could still be averted by some silent technology that would harmlessly detect bombs and weapons on would-be criminals.

Industry wonks imagine this technology would provide a “tunnel of truth” through which travellers could pass without stopping, unless of course the machines detected some dangerous tool or trace explosive on them.

But that day is a long way off, since none of the new technologies under consideration by the US government provides a way to do a truly complete search of passengers, experts say.

“With all the expense and complication they are doing with these body scanners, they have still not completely deployed something that does comprehensive detection on concealments by people,” an industry source.

The current star of the show is the body scanner, which has sparked uproar in the US public over the detailed body images it shows to the people working as screeners in airports.

The US government insists that advanced imaging technology – which uses millimetre wave or backscatter technology to either bounce electromagnetic waves off a person or project mild X-rays – is safe.

But critics point out it would likely miss explosives hidden in shoes or in body cavities.

An improvement to AIT that could sooth the sensitivities of body-conscious travellers is known as automated target recognition, which would allow the scanner to focus on any anomalies, such as a knife, and blur out the rest.

Screeners would see a stick figure or a blob of the person being scanned, and any suspicious area would be highlighted so that a security expert could proceed with a more targeted pat-down.

“The only concern I have about that is there is currently a high rate of false positives,” John Pistole, head of the Transportation Security Administration , told lawmakers earlier this month.