The chance of dying in an airplane is vanishingly small. The chance of being killed by a terrorist in an airplane is smaller still. Mark Stewart, a civil engineer who studies probabilistic risk, has put the odds at 1 in 90 million a year.

Looking at these figures dispassionately, one might wonder if the Transportation Security Administration has found the right balance between safety and convenience with its notoriously burdensome airport screening procedures.

The TSA seems to understand that the status quo is barely tolerable for many travelers and is seeking to reduce the hassle. It recently announced that it was extending eligibility for a prescreening program called PreCheck to all American citizens.

People can apply online before visiting an enrollment site in person, providing their fingerprints, passing a background check and paying $85 for a five-year term. In exchange, they will gain access to a special lane at the airport where they can keep their belts buckled, their shoes tied and their liquids in their carry-on bags (but still no more than 3.4 ounces, please).

PreCheck will provide a measure of relief for anyone who signs on. But it is absurd for the TSA to demand background checks and fingerprinting for what amount to small modifications in the screening routine. The agency could relax airport security for everyone without gravely endangering the traveling public.

It is time to stop pretending that annoying protocols like these are all that stand between us and devastation. The most effective security innovation post-9/ 11 was also the simplest: the reinforcement of cockpit doors, which has made it virtually impossible to hijack an aircraft.