Are municipal airports in the U.S. treated differently than most public places in regards to legal, holstered, loaded firearm carry? Is a municipal airport treated like a normal public place which requires signage or registration with a no-carry list to ban firearms from being carried on the premises, or...

... is a municipal airport treated like a government facility such as a courthouse, post office, or DMV office?

Or is there some other rule regarding guns that are loaded, holstered or otherwise carried on or about a person?

Airport terminals designed primarily for part 121 airline operations which are actively screened by the Transportation Security Administration are beyond the scope of this question.

Laws vary from state-to-state, so if carry is not legal in those states, then this question is not being asked in regards to those states, obviously.

Related: Are US pilots permitted to carry &amp; use their firearm in countries where guns are illegal?
As you hinted, it depends on the state. And the airport.

Some states allow travelers to carry their hunting rifles or pistols aboard general aviation planes. It is recommended that they buy the ammunition at their destination, if they can, for safety reasons.

Best answer I have is this:


  Any private pilot desiring to transport a firearm, weapon, or similar device must review the appropriate regulations and should contact the local airport management or law enforcement authorities for approval to land at any airport if any firearm is on board.


Source: AOPA

Another way to look at it, if you have your own private airstrip, who's to stop you? Just contact the local authorities of your destination before heading out.

For unconcealed firearms in a public airport:


  44 States allow lawful carry of firearms in the common terminal and baggage claim areas of airports.


Source: Florida Carry and CBS News (2008)

Disclaimer: contact local authorities before trying it, aka don't try this at home.