They may have a legal obligation to even if its a US airline under UK or EU legislation.
The key point is where the flight goes from and to.
The information below is only relevant to flights covered by UK law. To be covered, your flight must either:
- depart from an airport in the UK on any airline
- arrive at an airport in the UK on an EU or UK airline, or
- arrive at an airport in the EU on a UK airline
EU air passenger rights apply:
-
If your flight is within the EU and is operated either by an EU or a non-EU airline
-
If your flight arrives in the EU from outside the EU and is operated by an EU airline
-
If your flight departs from the EU to a non-EU country operated by an EU or a non-EU airline
-
If you have not already received benefits (compensation, re-routing, assistance from the airline) for flight related problems for this journey under the relevant law of a non-EU country.
EU means the 27 EU countries, including Guadeloupe, French Guiana, Martinique, Mayotte, Réunion, Saint Barthélemy, Saint-Martin (French Antilles), the Azores, Madeira and the Canary Islands, but not the Faeroe Islands. EU rules also apply to flights to and from Iceland, Norway and Switzerland.
Both are significant and important.
Where it gets even more complicated is with partner airlines. If you have departed on a flight from the UK and have a change in the US and the operator of the second flight is an American airline, you may still be covered as it was booked under UK legislation and the airline provides flights on behalf of a UK carrier (so you effectively have booked a flight with BA but part of it might be operated by a third party but your contract is still with BA not the US carrier - the key point is you have a single booking reference - it is counted as a single flight with a connection). In this situation, liability is with who you booked not the carrier itself.
The one to watch out for is flying with a Non-UK or EU airline for the RETURN flight. That's where you might get caught out as you aren't covered for this. You will be covered for the outbound but not the return. Unless its in your terms of the booking. This would be where you would use travel insurance.
There are also exceptions too - for 'extraordinary circumstances' beyond the control of the airline. These include:
Weather conditions incompatible with the safe operation of the flight,
air traffic control restrictions,
a manufacturer’s defect with the plane (where a recall has been made),
security risks
civil unrest
and airport strikes (but not airline strikes)
So you can be stuffed in these situations regardless anyway.
This is where you should think about your route / destination especially if you have a connecting flight. If you are planning to fly through an airport with a high cancellation rate due to weather or there's a high chance of civil unrest, you might want to think again. Deciding to go through or via somewhere at the height of hurricane / typhoon season, might not go so well. If there's an issue with civil unrest, then some airlines might over alternative options if the UK Foreign Office has issued an official warning. (Again this is where a UK or EU airline is probably better as they are more likely to offer this option).
You should also consider where you are connecting / flying over. For example: Air China offers much cheaper flights to Japan via China. But it flies over Russia. If for any reason a flight had to make an emergency landing whilst flying over Russia that could be problematic for ANY Brit in this situation. There are also warnings about even transiting through certain countries due to the enforcement of arbitrary local laws - even if you don't pass through passport control and the action happened in another country legally - eg social media posts. I know the UK government warn about this and Hong Kong is one of those places considered an issue currently with some companies advising that if passing through, you shouldn't take a phone with anything work related (eg apps or logins) and preferably just have a completely separate travel phone (device sanitation). It sounds crazy but it does matter.
The long and short of it, is you have more rights / are safer security wise across the board if you book flights with any UK or EU operator. They are also more likely to take responsibility for you in exceptional circumstances though this is not a given. This is also why non-uk/non-EU airlines are often cheaper for the same routes for long haul.
TBH I didn't know most of this until recently myself. Its not clear, its confusing and not well known.