Poznan remains one of Europe's more elusive business class prizes from the American West Coast, and there's no way around the truth of it: there is no nonstop option, so booking business class from San Diego to Poznan always means routing through a major hub, with Frankfurt, Munich, Amsterdam, or Warsaw serving as the practical gateways depending on which alliance you favor. Delta's transatlantic metal, often in partnership with KLM or Air France via Amsterdam, pairs well with LOT Polish Airlines' regional hop into Poznan, while United routes typically funnel through Frankfurt or Munich on Star Alliance metal before connecting onto LOT's Embraer or Dash fleet for the final short leg. LOT itself operates Poznan as a domestic-style feeder market, so your long-haul comfort is really determined by the transatlantic carrier you choose out of San Diego, whether that's Delta's One Suite on select 767/777 aircraft or United's Polaris business seats on its 787 and 777 fleets.
Having flown this corridor several times, my strongest advice is to build in a deliberate overnight or extended layover in Frankfurt or Amsterdam rather than a tight same-day connection — LOT's Poznan frequencies are sparse enough that misconnects can strand you, and a planned stopover lets you shower and reset in a proper lounge before the final short hop. An insider tip few mention: Delta's Amsterdam connections often allow access to the KLM Crown Lounge with quality shower suites, which matters enormously after a 10-hour transatlantic segment when your only remaining flight is a narrowbody with no flat bed.
January through March and October into November consistently offer the softest fares and least crowded lounges, as Poznan's trade-fair calendar (notably the Poznan International Fair) creates spring and autumn demand spikes that push premium cabins tighter. Given the routing complexity and fare volatility on this city pair, setting up automated fare alerts is genuinely the smartest way to catch a well-priced business class fare before it disappears.
