Comment by ale42
Detection by airport security might probably be avoided using the right type of explosive. I have no real idea about this, but I suspect that any nation-state with enough budget and know-how can manufacture undetectable or very hard-to-detect explosive devices. If the explosive is encapsulated in a sealed airtight container, which is properly "washed" after manufacturing, I guess there's no way to chemically detect the explosive inside. Not sure about how to avoid X-Ray detection but that's generally not the way explosives are actually detected.
And, is the device anyway going to pass through airport security? I guess the owners are not really travelling on commercial airliners.
The scanners only test for the signatures of common chemical structures of explosives, like nitro and nitrate groups, which make up the bulk of mass produced explosives. There are many lesser known chemistries for high explosives that will not be detected by these scanners. Probably the best known example actually used by terrorists are explosives based on peroxide chemistry but there are several others.