Hannover isn't a destination that rewards impatience, and neither is the routing required to reach it in comfort. There is no nonstop option for business class from Indianapolis to Hannover, so the real decision happens at the connection: Delta routes through Detroit or Amsterdam with a codeshare partnership feeding into KLM's network, American funnels through Chicago or Philadelphia into its transatlantic joint venture with British Airways, and United typically connects via Chicago or Newark into its Star Alliance partners. Each carrier will get you to HAJ eventually, but the domestic-to-international transition matters enormously here — a tight Detroit or Chicago connection during winter weather can unravel an otherwise pleasant itinerary. I've found Delta's Detroit hub to be the most forgiving for this routing, since it's a true hub built for these connections rather than a spoke bolted onto a bigger operation.
Aircraft matters as much as airline on this route. If your itinerary routes you onto a Delta long-haul widebody across the Atlantic, you'll likely experience the Delta One suite with a closing door on their 767 or A330 fleet, a meaningful upgrade over older reverse-herringbone configurations still flying on some competing routes. American's transatlantic joint venture flights increasingly feature the Flagship Suite on 777-200s and 787-9s, with the sliding door and genuine privacy that longtime flyers of this airline will recognize as a recent and welcome shift. United's Polaris seats, found on its 767 and 777 fleets, remain a solid if less flashy option — direct-aisle access on every seat is the key detail worth booking around, so avoid older configurations without it if you have a choice at check-in.
My insider tip: book the connecting domestic segment as late in the day as your itinerary allows if routing through Chicago or Detroit in January or February — this maximizes rebooking options on the same carrier if snow delays cascade, since these hubs run frequent shuttle-like frequencies to their transatlantic gateways. October and November also reward patience, as business travel to Hannover's industrial and trade-fair economy dips between major exhibitions, softening fares. Given how much these connection-dependent itineraries fluctuate week to week, setting up fare alerts for this specific city pair is the smartest move you can make before booking.
