Poznan's modest airport handles no widebody service from the US, which means every Indianapolis traveler heading there in a lie-flat seat will be routing through a major European or East Coast gateway — and after dozens of these connections, I can say the itinerary quality varies enormously depending on which carrier you choose. Business class from Indianapolis to Poznan requires at least one, often two, connections, with total journey times stretching well beyond the roughly 9 hours of pure air time once you factor in layovers; the most efficient routings pair Delta or United's transatlantic metal with LOT Polish Airlines for the final hop into POZ, since LOT operates the only meaningful direct European network into this regional airport. Delta's One Suite (on select 767/777 aircraft used on Atlanta or Detroit-Amsterdam pairings) or United's Polaris product out of Chicago or Newark to Frankfurt or Munich give you a genuine flat-bed experience for the long-haul segment, after which LOT's shorter regional business class — recliner seats, not lie-flat, but perfectly comfortable for the sub-two-hour hop — completes the journey.
My strong preference is routing through Chicago on United rather than connecting through Atlanta or JFK, simply because O'Hare's international terminal makes same-day Polaris connections onto LOT's Frankfurt or Munich flights far less stressful than the tighter windows you'll often find on the East Coast; if you have any flexibility, book a minimum 2.5-hour connection in Chicago to allow for immigration-free international-to-international transfers. Warsaw, rather than Frankfurt or Munich, is actually the smarter final connection point when schedules allow, since LOT's own hub gives you more frequent, better-timed flights into Poznan and reduces the odds of a missed final leg derailing your whole trip.
January through March and again in October and November consistently offer the softest business class fares on this corridor, as Poland sees minimal leisure demand outside summer and the Poznan trade fair calendar. Given how erratic premium award and cash pricing can be across three separate carriers and multiple connection points, setting up automated fare alerts for this specific Indianapolis–Poznan business class routing is the smartest way to catch the inevitable pricing dips before they disappear.
