Airline policy when a passenger is refused entry in both departure and arrival countries

You describe a somewhat hypothetical situation that is unlikely to happen in real life. While you might be able to find a few corner cases, they are not going to be indicative enough where any sort of helpful answer can come from the internet.

But to satisfy curiosity for the bulk of removal cases...

If a person arrives in a county with a visa, and they are found inadmissible by the Immigration Officer, the next step is finding out where the person is admissible and sending them there. This is done by the receiving country, not the airline. If the receiving country can't find out and make a positive, absolute determination, well then...

Welcome to Yarl's Wood. Or Toulouse-Cornebarrieu. Or Schwäbisch-Gmünd. Or any of the similar sites that is cleared for intake. The person will be sent there until a solution is reached. They will not return a passenger to a place that will not allow the passenger to enter.

This is explained clearly in the guidance...

While Paragraph 8(1)(c)(iv) provides for removal to another country or territory, (for example, if the passenger asks to be removed to a specific country), it would be unlawful for an immigration officer to give removal directions under this sub-paragraph if he did not have reason to believe that the passenger would be admitted to that country or territory. In these circumstances directions should be given for the passenger's return to:

• the country of which he is a national or citizen [8(1)(c)(i)];
• a country in which he has obtained a passport [8(1)(c)(ii)]; or
• the country in which he embarked for the United Kingdom [8(1)(c)(iii)]

and for the case where the person cannot be returned to the port of embarkation...

In such circumstances the immigration officer should serve an IS 83 on the owner or agent, suitably amended to make it clear that it is intended to give specific removal directions when the case is finally resolved. The refusal form IS 82 (paragraph A), should be annotated to read...

You mentioned the case of Mehran Karimi Nasseri, and there are some spectacular cases like Gary Glitter and Bobby Fischer. But these are so unique that they cannot be examined by a generic answer.

And for your direct question, airline policies are too diverse to even think about. Most of the time they will pay the fine (or costs) and then conduct an internal investigation to find out who was responsible for allowing the person to board. If it looks like an organized crime, they will get the police involved. If it looks like incompetence, the employee will face disciplinary actions.

If the airline brings the person to the country without satisfying the visa and/or passport requirements for the destination country, the airline is responsible for taking the person back, and may also be fined.

However, in your case, you are saying the person does meet the destination country's visa and passport requirements. He is just denied entry for other reasons. In that case, the airline is not responsible. The person is now the destination country's problem.

The destination country may give the person a choice of

1. Buying his own ticket (on whatever airline) to leave ASAP voluntarily. In this case, the airline of the new ticket will in turn check that the person meets the visa and passport requirements for the new destination country before letting him board. Or, failing that,
2. Being forcibly deported. If the person is put through deportation, the the country will be responsible for figuring out which country the person can be deported to (i.e. which country he satisfies the visa and passport requirements of) and arranging the transportation. Generally, having a country's passport guarantees entry to the country, so, if nothing else, the country of the person's valid passport should be a valid destination to deport to. (In the unlikely case that a country denies entry to someone with its own passport, well, then they will have to think of something else.)

And then if the next country the person goes to also denies the person entry, we repeat this process again.

As others have said, once you have been refused entry, the airline has little say in the matter, you will not show them your passport at the check-in desk in the regular way but be escorted directly to the gate by the police/border guards. Airlines have broad legal obligations to carry you back to your country of departure (in national and international law) but the local police usually makes the decisions.

That's not to say airlines always go along, an airline or an individual crew can obviously refuse to carry out a removal. After that, it's a matter of negotiation between the airline and the authorities, they might have to face some penalties, etc. but it's still their airplane. Usually, it's because the person being removed becomes agitated and the police escort reacts with aggressive tactics that passengers and crew find disturbing but it does occasionally happen.

If you have been removed in that way but cannot be admitted in the country you originally left, reasonable countries will not ask the airline to carry you again to your original destination. In some countries, that's explicitly specified in the law, e.g. in France. But it does happen, I have heard of a few cases of people who did two round-trips before one of the countries involved budged (sorry, no reference at hand but I am not thinking about celebrity cases, just some unlucky unknown travellers).

The alternative is to move the person to the regular deportation/removal system, which is a bit messy but deals with many other thorny cases including people who are being expelled after a court order, have been caught staying illegally in the country, won't say where they are from or lie about it, etc. The way this works is that you will be detained for some time while the authorities look for a country that is ready to admit you. That could be your country of citizenship but also some other third country, depending on the specifics of the case.

In any case, they should in principle get clearance from that country's consulate before putting you on a plane, especially if you don't have a valid passport, which is often the case (some people try to ditch their passport after landing in an effort to make removal more difficult).In this scenario (i.e. outside of a straightforward “bounce”), it's not necessarily the airline that brought the person to the country that will take care of the transport. The country deporting you might also pay for your tickets (and those of the escort, as applicable), possibly on another airline.

If there is no solution (e.g. because your country isn't safe or isn't cooperating), you could be detained for a long time, in some countries indefinitely, or possibly simply let go with a temporary visa and an order to leave the country by yourself (this happens regularly in France for example).