ANYONE WHO'S BEEN trapped in an aircraft with a crying infant knows that they can be little terrors. But terrorists? Hardly likely. It turns out, though, that infants have been stopped from boarding planes at airports throughout the country because they have the same names as potential terrorists on government watch lists. Some families with unfortunately named infants have missed their flights as a result, according to the Associated Press. This is, of course, ridiculous. But it also reflects the unthinking zealousness that has characterized some of the post-Sept. 11 bureaucratic and inflexible approach to security.

This latest development, though, underscores a deeper problem that persists with airport security nearly four years after the terrorist attacks: The passenger screening system remains a mess. Homeland Security Secretary Michael Chertoff acknowledged as much in a speech last month. "We are still dependent upon a pre-9/11 technology system to conduct the most elementary form of terrorist screening -- matching names against watch lists," he said. The list, he said, "is not fully automated for aviation screening, and it yields an unacceptably high number of false positive identifications, which drains our security resources and imposes a burden and inconvenience on passengers."

The elementary, common-sense solution outlined by Mr. Chertoff -- linking up the names on the no-fly list with more precise identifying information such as date of birth -- would, as the secretary says, "dramatically reduce the number of cases where travelers are delayed for questioning." But that task has turned out to be enormously complicated; there are huge technological hurdles to surmount, as well as legitimate privacy concerns to be considered. As a result, the Secure Flight program, once supposed to be launched this month, is still not ready for takeoff.

Mr. Chertoff has brought a useful dose of logical thinking to the homeland security job -- for example, ending the practice of confining airline passengers to their seats for 30 minutes in and out of Reagan National Airport. Indeed, the Transportation Security Adminis- tration, which administers the no-fly list, recently issued new guidance for dealing with children under 12 whose names turn up on watch lists. Passengers under 12 whose named are on the "selectee" list -- a larger, less exclusive list of people singled out for extra attention but not prohibited from flying -- don't need to be specially screened, as they once were. But if the unlucky youngster is on the no-fly list, it still takes a TSA official to sort it out and let the passenger board.

This seems like an unnecessary bit of hassle, particularly given the admittedly flawed state of the no-fly list. While the nation awaits Secure Flight, perhaps in the meantime Mr. Chertoff could move further in the direction of Sensible Flight.