Delta and United Airlines are skirmishing over fares from several California airports to Stockholm, Sweden, for August departures. A fare war including American Airlines is continuing for flights from New York to Scandinavia. Iberia Airlines is in the fight also.
Check the airline websites, Google Flights and/or your favorite online travel agency (Expedia, Priceline, Travelocity, etc.) to see what is available. Look for round-trip fares in the $300s from the East Coast and the $600s from the West Coast.