Just because TSA doesn't prohibit it doesn't mean an airline can't. TSA seems more concerned with imminent threats rather than something might cause an issue way down the road. Hawaiian doesn't mention pure salt as prohibited, but they do prohibit salt water --

http://hawaiianair.custhelp.com/app/...check-in-items

Simple a salt.

Not allowed on planes.

WRONG....

In the past 6 months I have been traveling back and forth from Brazil. There is a brand of organic sugar I love and of course bring a few bags back for baking, coffee, etc.

I asked AA at GIG and GRU if it was ok to carry this on... the answer was yes. I have gone though customs and TSA with bags of this sugar at JFK, LAX, DFW, MIA... NO PROBLEM.
This sugar is crystallized so it looks like sea salt.

This sugar is far superior to any sugar I've had in the US, I'm very picky about what I put in my coffee.

Not to put too fine a point on it but I'm sure you do know that sugar and salt aren't the same thing, right? ;) Just making sure. :)

My bet is that the contract security agent just thought it was unusual that somebody would travel with a big bag of salt. Why go to the trouble of traveling with salt when it is easy to purchase this condiment/spice virtually anywhere in the world? It could mean you have something to hide.

Remember, those contract agents are used to seeing the same kinds of stuff in people's luggage over and over again, all day long. They know what is "normal" or typical for somebody to have in a suitcase when departing from that particular airport. Anytime they see something unusual or out of the ordinary, they are paid to be suspicious, even if it is not a threat.

Furthermore, customs agencies across the world sometimes find prohibited goods/items concealed in consumer dry goods like powdered milk, infant formula, spices, etc. Sometimes smugglers even use the empty packaging of consumer items because it looks so innocuous at a glance. There are lots of episodes on YouTube showing it. Basically, anytime they open bags and see a large quantity of a random food item/ingredient that can be easily purchased locally upon arrival, they wonder why somebody would go to the trouble of shipping it or traveling with it from far away.

Furthermore, as noted upthread, USA-based airlines are private companies and can decide to prohibit whatever they want aboard their aircraft, within the confines of the law. If AA hires contract security and instructs them to prohibit salt in carry-on bags, all you can do is write to AA and inquire about the policy.

I'll give you one reason, from personal experience. Often I would stay in a kitchen-equipped studio/condo for a week or two, and either
- bring smallish quantities of things you can't buy in small supply, or
- buy more than I need and bring the rest back

What can I say -- I was cheap and hated to waste.

And, yes, I got flagged once at X-Ray due to a few pounds of rice. Once they opened and saw the clear bagful I was good to go.

Exactly. It's just not what they are used to seeing. So they were more interested.

I gave up over $1,000 usd in dead sea salt products when the liquid ban occurred flying from TLV>PHX while making a connection. I had a choice to check the products as baggage but I knew I would miss my flight. This was early on and the security gals put all of it on the table to take home as it was just the 1st day of the no liquid ban

Maybe that's why they're changing their planes over to composite materials? :D

Going back to what the threat to aviation security would be. So the logic would be that a person trying to cause harm to an aircraft would:

1. Board a flight, and place the salt in a location of the aircraft somewhere critical that is also aluminum.
2. Note the tail number of the aircraft.
3. Hope maintenance misses it for many months.
4. Keep reading the news looking for stories of downed aircraft and compare the tail number from step two.

Seems a little far fetched to me.

I travel with a one-quart sized reusable plastic baggie containing 2-cups of a white powder mix in my check-in bag: one cup of sea salt and one cup of baking soda. It's for nasal irrigation.

EVERY SINGLE TIME TSA opens the bag and inspects it. Overseas? They have NEVER opened my bag to inspect it.

Annoying. I know darn well they are looking to see if it is drugs. Gotta love that mission creep . . .

Though very highly unlikely, certainly theoretically possible.

TSA is not contract security and isn't hired by the airline. They are an agency of the federal government.

I don't think TSA operates security in El Salvador.