Trondheim rarely shows up on business class itineraries out of Los Angeles, which is exactly why the routing deserves careful thought rather than a reflexive booking. There is no nonstop option here: business class from Los Angeles to Trondheim always routes through a European hub, and the three real contenders are SAS via Copenhagen or Stockholm, Lufthansa via Frankfurt or Munich, and KLM via Amsterdam. Total journey time from LAX runs well beyond the 11.5-hour flying time once you account for the connection, so hub choice matters as much as airline choice. My preference over dozens of trips has been SAS through Copenhagen — their A330/A350 business class delivers a comfortable flat-bed product and CPH's proximity to Scandinavia makes the final Trondheim hop, typically on a Boeing 737 or A320neo in a domestic-style business cabin, feel seamless rather than punishing.
Lufthansa's routing via Frankfurt appeals if you're already tied to Star Alliance miles, and their long-haul business class seat on the 747-8 or A340 fleet remains a solid, if not groundbreaking, product; just budget extra buffer time at FRA, where connections can involve a security recheck between concourses. KLM via Amsterdam is worth considering in shoulder months when Schiphol's connection times to Scandinavian cities open up, and their World Business Class seat on the 787 and A330 fleet is consistently reliable. My insider tip: because Trondheim's Værnes Airport has limited daily widebody-adjacent connections, book the final short-haul segment as early in the morning as possible — Scandinavian carriers often price this leg more favorably before midday demand from Oslo and Bergen connections pushes fares up.
May through September brings the best combination of fare softness and daylight — Trondheim's long summer evenings make arrival fatigue far more bearable than a dark Norwegian winter touchdown. Given how thinly these three carriers compete on this corridor, fare swings can be sudden and hub-dependent, so setting up automated price tracking for Los Angeles to Trondheim business class is the smartest way to catch a fare dip before it disappears.
