TSA is supposed to let it through if it's below 0.3 D9-THC
GCMS will detect THCA if derivatized - https://www.cannabissciencetech.com/view/a-brief-review-of-d... - I find it hard to believe that you couldn't get a non-derivatized GCMS thrown out in court when it's known that GCMS will cause THCA to decarboxolate into THC.
I suppose I should stipulate I'm not a lawyer and there are obvious risks to possessing something that looks exactly like an illegal product.