But in this case, a firearm could not have been constructed from the parts. See here

Guns have been on aircraft almost ever since aircraft were invented. Because so much is said about risk, and risk is likelihood and outcomes, it'd be interesting to ascertain the frequency of guns on aircraft against the outcomes. My guess is that the frequency is and was much higher than any of us would guess, and the bad outcomes are from a miniscule number of cases, with most of the bad outcomes in the 60's (domestic) and 80's (International).

And that's the risk from real guns. I can't think of any commercial aircraft event that involved zip guns. None. Perhaps you know of one.

That's the frequentist view. The probalist view would be informed by the guns discovered at the checkpoint. I can't think of any that were carried by someone who intended harm. Perhaps you know of one.

In the extant situation, the Pasco sheriff is involved instead of Hillsborough. That tells me that the gun was related to something off-airport, and only disposed of in the airport.

Altogether a yawner of a story for airport security.