1. The best connection is to fly to Berlin BER - then train in the train station to Magdeburg via Potsdam HBF (please use connections with only one change) - tickets between 20-40€ -

2. Frankfurt/Hamburg/Dresden are also possible - but the train connections are longer and not within the airport

3. Leipzig and Hannover are the closest airports - depends on whether you rent a car

for Train use this Links : https://www.bahn.de/