PSA: It is legal to possess Kratom in an airport where it is legal
Kratom is not federally banned, so it is legal to possess after the security checkpoint, and if the airport is in a place where it is legal then it is also legal to possess before the security checkpoint.
Recently I packed Kratom in my carryon in a legal state, and had no issues getting it past security. If they were to search your carryon for some reason and discover it, then maybe as a precaution you could throw it away before boarding your flight, in case they tip the local law enforcement of your destination. But for going through security itself, I see no reason why you would be prevented from bringing Kratom, because it is legal to possess there.