Why secure airports when it's planes that fly?

Airports in the US are usually not secure, but the passenger terminals usually are. It makes sense to secure the passenger terminals instead of the individual planes to reduce the amount of equipment and staff needed. LAX for example has 150 gates across 8 terminals. Securing each plane would mean placing TSA agents, metal detectors, scanners, and X-Rays at 150 gates instead of just 8 terminals.<p>Come to think of it, US airport security is pretty weak compared to an airport like Manila NAIA (in the international terminal). Passengers get checked curbside for passports and tickets, and again at the door. Then they must pass through metal detectors and bag scanners to get into the ticketing area to get boarding passes. Boarding passes and ID are checked again at immigration. Then there is another bag scan and metal detector to get into the passenger terminal. The last check is the most thorough. To get to the individual gate, there is a checkpoint with one station where all carry-ons are opened and inspected, one station where passengers remove their shoes for inspection, and a final station for a pat-down by security. This last security check must be repeated every time you go to the bathroom or visit the shops or restaurants.

An airport can contain a high number of boarding gates, not all of them are used 100% of the times. It would be very inefficient to allocate space and equipment for security check at each boarding gate.<p>Furthermore security checks can induce a variable amount of delays, it's better to perform them a little earlier than actual boarding in order to amortize for eventual delays.<p>One solution would be to have another waiting room after the boarding gate security check, and force people to pass to the "boarding security check" earlier than needed, forcing them to wait in the boarding room.<p>But there is no need to allocate a single waiting room for each boarding gate, as you can assume that each boarding gate security check is performed with the same criteria, you can have a single waiting area in order to optimize space. You will have then second level boarding gates for actual boarding.<p>And of course, since people are waiting there doing nothing, you can monetize them by providing shops, bars etc.... but wait, we are back where we started