Airline Security: How Safe Can We Get?

The system has been vulnerable for years. Marginal improvements aren't enough

Just how does a plane become a guided missile? The answer, in part, is that the air-security system in the U.S. is porous in so many ways that a breach was not surprising--only the incomprehensible dimension of it. For aviation experts, who are all too familiar with the gaping holes in the nation's vast network of 100 large airports, there was a sad, easy explanation for Sept. 11: you get what you pay for.

For years, countless critics, from government watchdogs and consumer groups to industry officials, have railed against and exposed the nation's lax, inadequate airline-safety net, one they...