Just to clarify, any flight which originated in the EU for any airline, or any flight coming into the EU operated by a EU airline (important for codesharing the operating airline counts not the issuing). Also the amount of compensation depends on delay and overall length of travel.
I have purposefully been only booking on EU airline operated flights only after having been bitten twice before where I missed a connection and had to wait 7h (my home airport has only very few flights to the major intercontinental hubs, meaning any connection delay ends hub being quite significant). I have collected several thousand euros in delay compensation since then (multiple airlines) , never had to fight the airline to get it, simply filling in a form.
I have purposefully been only booking on EU airline operated flights only after having been bitten twice before where I missed a connection and had to wait 7h (my home airport has only very few flights to the major intercontinental hubs, meaning any connection delay ends hub being quite significant). I have collected several thousand euros in delay compensation since then (multiple airlines) , never had to fight the airline to get it, simply filling in a form.