United Airlines has tickets at $334.43 round trip for LAX to Barcelona departing late July in Basic Economy. That means no checked bag or add $160 for a checked bag each way. Still, $495 is a good summer fare deal.
One thing I can thank the now defunct WOW Air for is teaching me how to travel really light. I am heading to Europe today with a Scandinavian SAS GoLight fare and only an 8kg carry-on bag weight limit for ten days travel. United is not as restrictive on carry-on bag weight.
United Airlines Los Angeles LAX – Washington IAD – Barcelona BCN – (Swiss Airlines) Zurich – LAX
An overnight in Zurich might negate the ticket value for some if you do not have hotel points to redeem. I enjoyed Zurich a few years back on a daytime 8 hour layover with efficient airport transportation to the city center. There are several airport hotels.
Air Canada and American have tickets around $525 during this time frame.