No need to dis-assemble it.
Check the TSA rules and the rules of the airline you will be flying. I just
did a Las Vegas and back trip from PDX with 3 handguns--no problems.
Guns were in a locked hardcase inside a softside suitcase.
You MUST declare them (and ammo) at check-in.
You may be asked to unlock the case or show that they are unloaded.
Read and understand the rules--keep a copy of the rules with you.
Flying with guns isn't a big deal but it can be a bit of a pain in the butt
if you run into an agent that doesn't know the procedure.