In my more depressed moments, it seems to me that high speed air travel, like all mass transport, is dead. :-(<p>There are too many religious&#x2F;political idealists. When they get serious 3D printers, it should be possible to build metal objects (like the framework of luggage) around explosives, including batteries. Put the resulting metal object in bleach and rinse for a week. It should have no detectable explosives and be immune to X-rays and most other radiation.