Star Alliance airlines Lufthansa, SWISS and United are offering very good deal from Germany to Califronia. Return flights between Dusseldorf and Los Angeles are available already for €315. This is including all charges and fees. There is one short layover in Frankfurt, Zurich or New York depends on the routing you choose. At this moment plenty of travel options to sunny California are available in upcoming winter season 2016/2017..
Promotional sale with Lufthansa / SWISS and United is valid for flights departing from Germany to Los Angeles between 7th of November and 9th of December, 25th of December 2016 and 6th of April 2016. Max stay 4 months.
Booking sample of cheap Star Alliance flights from Dusseldorf to Los Angeles from €315! In this case you will be departing from Germany to California on 17th of February 2017. Your return flight from North America back to Europe would be on 3rd of March 2017.