Starting in June, Ethiopian will fly the route three times per week using a brand new Boeing 787!
Until April 30, for travel between June 20 and November 31 (except July 11 to August 14, it seems, when you pay a bit more), Ethiopian is selling economy return flights for just €499. You can fly to either Addis Ababa or Los Angeles for that price.
Over the Summer this is an astonishing deal if you can find the seats. British Airways wants over £1,100 for Heathrow to Los Angeles on many days over the Summer. You can save £750 by taking the Ethiopian service!
The first bit of bad news is that the flight times are terrible. Ethiopian leaves Dublin at 6am so you would need to stay in the city overnight. The return is OK, landing at 18.30 in Ireland.
The second bit of bad news is that, according to this Business Traveller article, passengers will not clear US immigration in Dublin. This means that they will need to go through the often lengthy immigration process in Los Angeles.
The €499 price which is promoted in this press release I was sent is not available for all dates. It is out there, though – Expedia quotes £380 including its fees for 12-19 October for example. More digging may bring it up for peak dates. The lowest business class fare I found was a very unbargain price of £2,450.