This isn't the first time I've wondered about this, but I can't seem to find a clear answer.
Is it legal? May one take a flight, say, from Virginia to Florida, with a transfer through JFK? Obviously New York is highly restrictive, especially to nonresidents, but would this conduct be protected by Federal laws dealing with traveling with firearms?
I did it a few months ago and I almost had a problem. Long story short...
Was traveling from ME back to VA and had a layover in La Guardia. My flight got majorly delayed and they were expecting it to get cancelled. I spoke to the USAIR supervisor (who was a complete moron) and he said it was their policy that if the flight got cancelled, they are REQUIRED to give me my baggage back. (This policy is only if I were to take a flight the next day, they said they WILL NOT keep baggage overnight)
I told him the situation that I had a checked firearm in my luggage and his response was basically, "not my problem, have a nice day." So I started to freak out, and went to find a TSA supervisor. I also spoke with a policeman at the same time and told them both my situation. I had heard horror stories of people getting stuck in NY and then having to reclaim a firearm and getting tagged with some BS weapons charge.
The TSA supervisor told me that as long as I have the orange tag in my gun case (the one from the initial airport that states it's unloaded), they don't have a problem with it. That tag says time and date, original airport, etc. so it proves that I originally had it in ME. I asked for his contact info in case something happened, and he gave it to me. Luckily my flight was only delayed for 6 HOURS!!! and i flew home to VA without having to re-check my baggage.