Split's compact airport and dazzling Dalmatian coastline make it one of the more rewarding endpoints in Europe to reach via a premium cabin, yet there is no nonstop option—every itinerary for business class from Chicago to Split routes through a European gateway, most sensibly via United's own hub network or Star Alliance and Oneworld partners. United flies its Polaris-configured 787s and 777s nonstop from O'Hare to Frankfurt, Munich, or occasionally Zurich, from which Croatia Airlines (OU) operates a short regional hop into Split—typically under two hours, on an Airbus A319 or A320 without a dedicated business cabin, so treat that final leg as a formality rather than a luxury experience. American Airlines routes through London Heathrow or occasionally Zurich, connecting onto partner metal, and its Flagship Suite on the 777-300ER out of Chicago is worth angling for if your itinerary allows a Heathrow transit with enough buffer to clear the T3-to-T5 connection comfortably.
Having flown this corridor across several summers, I've learned that the real strategic decision isn't the transatlantic carrier but the connection city: Munich and Zurich offer faster, calmer transfers into Split than the sprawl of Frankfurt or Heathrow, and both have strong Star Alliance lounge options if you're on United metal with Polaris seats that convert into fully flat beds—ideal given the long transatlantic haul before a short intra-European hop. My insider tip is to book the OU connection with at least a 90-minute buffer during July and August, when Split's airport handles a disproportionate crush of leisure charter traffic that can back up immigration and ground handling even for connecting passengers arriving from a business cabin.
Shoulder season—April, May, September, and October—consistently offers the best combination of award and revenue business fares on this routing, as Dalmatian coast demand cools while daylight and weather remain excellent for exploring Split's old town before or after your flight. Given the multiple routing options and fluctuating partner award space between United, American, and Croatia Airlines, setting up fare alerts is the smartest way to catch a premium-cabin deal on this route before it disappears.