Mr. AR-15 Open Carry was trolling for law enforcement overreaction, got what he was seeking.
Sometimes, when I pick up visitors, I park in the "A" lot for two bucks and then carry (concealed) in the pre-security side of the Manchester-Boston Regional Airport (MHT) -- no signs, no drama. And last year a handful of FreeKeene-affiliated trouble magnets opened carried long arms at MHT while handing out literature, and were harassed... for leafletting, not for their rifles.
The Litchfield PD who staff MHT are very aware of NH law on open carry.