To Munich Airport

Last time I checked, which was admittedly years ago, a taxi from downtown Munich to the airport cost over 50€ for the taxi, possibly more for luggage. I imagine it's even more today.

For 5 people, an MVV Partner Gesamtnetz Tageskarte costs 21,30€ (4,26€/person), 33€ for 6 (5,50€/person). With the MVV ticket, you can travel by bus, streetcar, or U-Bahn to any S-Bahn station and from there by S-Bahn to the airport.

Or, you can stay in Freising, sleep later, and spend only 2,60€/person for the 20 min bus trip to the airport in the morning.

It's most expensive to take a cab, and it's a long ride. I'd avoid it if possible and go for one of the options Rick lists in our Germany guidebook:

By Plane
Munich’s airport (code: MUC) is an easy 40-minute ride on the S-1 or S-8 subway, each of which runs every 20 minutes (starting at 4:00 in the morning and continuing until almost 2:00 in the morning) between the airport and Marienplatz and the train station. While you can buy a single ticket for €10.40, the €11.70 Munich Gesamtnetz day pass (a.k.a. the "Airport-City-Day-Ticket"), which covers public transportation all day, is worth getting if you’ll be making just one more public transport journey that same day. (To buy it at a ticket machine, first press “MVV Münchner Verkehrs- und Tarifverbund,” which displays the array of ticket options. No need to validate the pass.) Groups of two or more should buy the €21.30 Munich Gesamtnetz partner day pass, which gives up to five adults the run of the system for the day (for more info on Munich transit passes, see page CROSS-REF: Paragraph). The trip is also free with a validated and dated rail pass. The S-8 is a bit quicker and easier, as the S-1 line has two branches and some trains split--if on the S-1 to the airport, be certain your train is going to the Flughafen.
Another alternative is the Lufthansa airport bus, which links the airport with the main train station (€10.50, €17 round-trip, 3/hour, 45 minutes, buses depart train station 5:15-19:55, buy tickets on bus; from inside the station, exit near track 26 and look for yellow Airport Bus signs; www.airportbus-muenchen.de). If you’re traveling alone, going round-trip, and not using other public transport the same day, the bus saves a few euros. Avoid taking a taxi from the airport, as it’s a long, expensive drive; it’s better to take public transport and then switch to a taxi if needed. Airport info: tel. 089/97500, www.munich-airport.de.

Slight technical correction. S1 and S8 are not the "subway".

• U-Bahn = Underground, aka Métro aka Subway. Lines are numbered U1, U2 etc.
• S-Bahn = Suburban / Commuter Railway. Lines are numbered S1, S2 etc.

S-Bahn is the same as "RER" in Paris and other French speaking cities, and other names in other languages.

For people who aren't habitual public transport users, any underground train with stations close together is a "subway". Of course, S-Bahn and U-Bahn are quite different things, but it's a bit too pedantic for this board, I'd say...

S1 and S8 are not the "subway".

@Chris, who (on this post) said they were? (Oh, I see. Casey did call it a "subway".) Some of our readers don't understand the difference, but a lot of people are familiar with the transit system in New York City. The U-Bahn is like the subways, underground and only in town. The S-Bahn is like the Long Island Railroad, underground in the city, but goes way out into the suburbs, above ground, a commuter rail line. In some places, the S-Bahn shares the rails with regular trains. The S-Bahn carriages are larger and heavier than the U-Bahn carriages.

The S-Bahn are run by the Bahn, so rail passes can be used on them. Tickets from a cities Metro system (MVV in Munich) can also be used on the S-Bahn. The U-Bahn is part of a local transit district, here the MVV, . They can be used with a local ticket (eg, MVV) or with a Länder-Ticket (Bayern-Ticket), but are not included with a Eurail or German Rail pass.

To expand on what Casey said, the departure platform at the Hbf Tief (underground) station is a central platform with all trains going by on one side or the other. S1s going east on Gleis 1 say "Ostbahnhof" and are coming from the airport, not going to it. S8s going west on Gleis (track) 2 say something like "Herrsching" or "Wißling" and are coming from the airport. DON'T GET ON ONE OF THESE TRAINS.

S1s going west on Gleis 2 will say either "Flughafen" or "Freising" and are going to the airport. S8s going east on Gleis 1 will say "Flughafen".

Despite the S8 taking less time, if an S1 is coming next, you'll get to the airport sooner on it. Wait on the central platform and take the next train going to the airport regardless of direction. If you take the S1, sit in one of the back cars (they will probably say "Flughafen"). If there aren't a lot of people in the car with suitcases, you probably have a wrong car. When the train gets to Neufahrn, it will split, with the front cars going to Freising.