Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from South Bend to Frankfurt am Main Airport as you normally would.
Most people fly from South Bend/Michiana (SBN) if they book a flight from South Bend to Frankfurt am Main. On average, South Bend/Michiana has 0 outbound flights to Frankfurt am Main per day from 2 airlines. South Bend/Michiana is conveniently located just 3.4 mi from South Bend’s city center.
There are currently 3+ open flights from South Bend to Frankfurt am Main Airport within the next 7 days for less than $1,700.
These are just IATA (International Air Transport Association) codes. They are used in aviation to identify and differentiate airports. That’s why a South Bend/Michiana Airport to Frankfurt am Main Airport flight would often be abbreviated as a SBN to FRA flight.