The other option is to fly BA to Toronto. There you can get many cheap charter flights to Cuba without the hassle.

Yes, AA will not accept any part of the ticket that has CUBA in the fare calculation. AA will not issue a ticket with HAV in its itinerary. Other airlines will, but have been instructed not to issue AA segments in it.

Return flights CUN-HAV-CUN 150-200 US$. Flights leave all the time.

So what about Flight LA587 that goes from CUN-HAV-SCL?

I want to take this CUN-SCL, will this be allowed? Not actually stopping in HAV (not on this ticket anyway), but the plane according to the timetable will touch down there.

Does this break the rules?

It is allowed provided that you have no AA segments on the same ticket. If you attempt to use this ticket on an AA flight, it will be confiscated (required by current US law, so AA has no discretion in this matter). Whether or not you would be able to obtain a refund or replacement ticket is between you and the airline that issued the ticket. AA is prohibited from dealing with you as soon as you present the ticket, unless you have a waiver from the US State department allowing you to do commerce with Cuba (easier to get than you would imagine, but only for US citizens). Even though you are not leaving your flight in Cuba, it is paying landing fees there, and that qualifies it as "doing commerce with the enemy". BTW if you require a visa or visa waiver to enter the US, this would disqualify you for future US visits (unless the law is changed).

Yeah, that's what I meant, so the transit through HAV, even though HAV is not listed on the ticket anywhere, the US customs or whatever will still pick up on it somehow?

So you can't do CUN-SCL on a xONEx unless you have no AA segments? That's not good.

I haven't a clue about laws but I do know several non-US residents who regularly visit Cuba and the US. Edit: and have been doing this for decades.

I don't either, but I believe that the embargo extends to citizens and resident aliens. If it indeed applies to others, it's news to me.

Thanks, but I think the point is missed. As a non-US citizen I can go where I like, including Cuba, but the rules (due to regulations from US Government) prevent any travel "via" Cuba if I travel on AA.

So is CUN-SCL via Cuba? Arguably yes it is, and if QF won't ticket it, fine, I can buy another segment for NA and be done with it. A bigger problem would be turning up for an AA flight and having the whole thing confiscated. That would be bad.

So unless anyone *knows* that you can do CUN-SCL then might be best to pay the extra segment and not have to risk anything...

Another approach would be to ticket a different itinerary, fly all the AA segments before that flight, and then reticket (not on AA stock) CUN-SCL. A bit of a nuisance though.

I don't think the point was missed. My personal belief is that you may be able to ticket it, but you may have some trouble if someone picks up on the routing. If the treasury department gets wind, they will care very little about a semantics argument relating to direct flights. What they will care about is that AA profited from a ticket that benefited the embargoed country, even if that benefit is in the form of landing fees. Then again, how would they find out? If you're this concerned, I would personally not take the flight. Go through Mexico City. I am sure you could find a reasonably priced flight from Cancun.

The fine points of the law (Trading with the Enemy Act, the Cuban Democracy Act of 1992 and the Helms-Burton Act of 1996) are that the prohibition is on doing business with Cuba. It applies to US citizens and resident aliens, and to US companies doing business anywhere in the world, including foreign subsiduaries. Basically a license is required prior to paying USD 1 to Cuba. So travel to Cuba is not prohibited, but paying for it by US companies is prohibited. This unambiguously covers a OWE ticket with AA segments that touches Cuba even if it is just a tech stop (and the LA flight isn't a tech stop). So AA is required to confiscate such a ticket when it is presented to AA (and is prohibited from selling such a ticket). Failure to do so has severe penalties. Given the scale of the penalties, and the small number of flights that touch Cuba, I would guess that the AA computer system is programmed to scan for all the flight numbers that violate the Cuba embargo. So I would say there is little scope for human error or discretion on what to do (most likely a high level supervisor over-ride is required, beyond the agent's capabilities).
The zeal with which the US govt enforces the embargo varies greatly. There was a big crackdown in 2003 for various reasons. Many Cuban-Americans in Florida visit Cuba each year, most in violation of the embargo, but they have the political clout to avoid any repercusions. The US govt tends to pick non-US citizens -- who do not have the right of appeal or voting power -- to make examples of. If you travel to Cuba and then enter the US, be prepared to show the country of purchase for every single item in your luggage; otherwise it will be deemed to have been bought in Cuba and confiscated. We all travel with original notarized receipts for all our clothes, don't we? In 2003 there was a famous case: US customs agents in Montreal would watch the pax exiting from the plane arriving from HVA and if they connected on to the US, they would get special treatment. The US customs inspection is done on US soil in Canada, but the HVA flight arrived on Canadian soil where the US agents had no right to observe the arriving pax. It was over the line, and doesn't currently happen, but it shows the seriousness of this particular "game".

Nor do I, in a thread there are many side points, not just the main one in post #1. One such tanget point in this thread was the claim that non-US residents/citizens would be banned from viiting the US after visiting Cuba.

Right. I agree with most or all that you have written. But you have written about citizens, resident aliens or certain companies. What I said is that I do not know that it applies to non-citizens and non-resident aliens, i.e. a visitor, which would be who would be entering the US on the visa waiver. I am not saying it doesn't, I am saying that I am not sure that it does (res aliens, citizens and companies, I am sure about)

Cubans living in the US are actually allowed to go to Cuba as an exception to the embargo. Most US based legacy airlines, including AA, have flights to Havana, which, from my understanding, are very lucrative. A lot of them shuttle Cuban nationals. IIRC, they can go every two years.

I can tell you from personal experience that it is a total pain in the ... to get permission to go. I went through about 80% of the process and hit a brick wall. This was 2002 when the tightening and cracking down was begun. Things always get tighter at election time.

As far as the CUN-SCL question, I cannot help but question whether the computer systems are smart enough to look for through flights that happen to connect through Cuba since there is probably only one or two. That being said, does anyone really want to risk a $5000 or $10000 ticket on a computer being wrong? The rule is that you can't go through Cuba and, as I said, the treasury department is not going to care much about your argument that it was a through flight and not a stop or connection. Personally, I would go back through the US or take a short hop to Mexico City.