Originally Posted by flarmip

If this was a simple MIA-LHR booking made under the AA flight number then I'm afraid EU/UK261 doesn't apply. For flights departing outside the UK/EU, these regulations generally only apply if the flight is operated by a UK/EU airline - hence it's always better to fly with a UK/EU airline when heading east over the Atlantic. Bizarrely, they do apply to foreign airlines if the flight departs the UK/EU. Totally illogical and inconsistent but there you go.

AA may offer you something as a gesture of goodwill but I don't think you are legally entitled to anything here.