There is no nonstop option for business class from Baltimore to Split, so the routing itself becomes half the strategic puzzle on this Adriatic itinerary. What works best, after many iterations, is pairing American Airlines' transatlantic metal—typically a 777 or 787 with Flagship Business's reverse-herringbone seats—into a European gateway, then connecting onward with Croatia Airlines (OU) for the short intra-European hop into Split. Delta is the other reliable option, routing through Amsterdam with its A330 or 767 Delta One suites before a partner or codeshare connection covers the final leg. The key fact worth knowing: BWI has no direct long-haul business class service to Croatia, so your comfort hinges almost entirely on which European hub you transit and how tight that connection is timed against Split's seasonal flight schedule.
I've found Amsterdam to be the gentler connection of the two—Schiphol's layout is forgiving for a business-class passenger moving between a long-haul arrival and a short OU or KLM-operated regional flight, whereas London or other congested hubs can eat into a layover fast if your Flagship Business flight lands late. One insider trick: Croatia Airlines' Split-bound flights from continental hubs are often operated with smaller regional jets that don't offer a true business cabin, so on the final leg you may simply be paying for flexibility and priority boarding rather than a lie-flat product—factor that into your seat selection and don't expect Flagship-level service all the way to the Dalmatian coast.
Split itself is a seasonal airport, with flight frequency dropping sharply outside the May-to-September tourist surge, which is precisely why April, May, September, and October reward patient shoppers: airlines discount business fares to fill planes before and after peak demand while weather along the Adriatic remains glorious. Given the moving parts across three carriers and layover cities, this is a route where fares swing unpredictably—setting up automated fare alerts is the smartest way to catch a premium seat before it disappears.
