Overnite in Munich - Hotel at Airport or in Town?

You can find this topic addressed at https://community.ricksteves.com/travel-forum/germany/munich-airport-hotels, and probably other posts in the German Q&A part of this Travel Forum.

The Best Western Park Hotel located in Erding is very convenient and a short ride to the airport. Across the street from the hotel is an S-bahn station where you can park the car overnight and take it into the city. I believe it's a 45 min. ride into Alstadt Munich. On the way to the airport, there is a 24 hr. gas station with an attendant.

We stayed at this Best Western and highly recommend it as well. We took a taxi to Therme Erding which is a huge great thermal bath soak (boasted as the largest in Germany) for a couple of hours to unwind. Beware they have textile and non-textile areas. Next morning, we took a taxi to the airport. Very convenient. The S Bahn into town seemed to take about an hour as Erding is the last stop on the line away from town. The hotel had a nice restaurant and other restaurants within a couple of blocks walking distance.

I've twice spent the last night before a morning flight out from MUC in Freising. Freising Bahnhof is a 20 minute, 2,60€ bus ride from the airport; buses run every 20 minutes. The best place to look for accommodations is on the Freising website, www.freising.de. An English language list of accommodations is here. One place in Freising that comes recommended is Zur Gred. Another place that looks promising is Bayerischer Hof. Both are within a ½ mile of the Bahnhof and the bus to the airport. Both offer double rooms for less than 100€, including breakfast. Freising is the home of Weihenstephan, the world's oldest brewery and their pleasant beer garden.

I second Astrid's recommendation on a relaxing visit to Therme Erding the night before your flight.