By plane
Stuttgart has an international airport which is served by all major carriers. Frankfurt international FRA, the busiest airport in mainland Europe, although not in Baden Württemberg, is well within reach by train 1 hour from FRA to Stuttgart main station via the high-speed ICE connection. Low-fare airlines offer services to the local airports of Karlsruhe-Baden Baden and Friedrichshafen.
Travellers beware: "Frankfurt Hahn", the big hub for low-fare airlines, should not be confused with FRA. In stark contrast, it has no train station and is in a rather remote location. It is possible to get from Hahn into Baden-Württemberg rather conveniently, but it definitely takes a lot longer and is much more hassle than from FRA.
For the southern part of Baden-Württemberg, the airports in Zurich, Switzerland, and the EuroAirport Basel-Mulhouse on French territory are convenient, too.
By train
All major cities are well connected through the Deutsche Bahn rail system. Ulm, Karlsruhe, Mannheim, Heidelberg, Stuttgart and Freiburg even have ICE connections slick, comfortable, white high speed trains travelling at up to 190 mph (300km/h). Tickets can be booked via the Deutsche Bahn Website (http://www.bahn.de)
Baden-Württemberg as well as some other regions in Germany offers a special regional train ticket in this case, the Baden-Württemberg ticket. It is valid for one day from 9am. With this ticket up to five people can use all regional trains within Baden-Württemberg for 21 EURO for a single ticketAdd 4 EURO per person afterwards.That means you can use all trains except InterCityIC, InterCityExpressICE, EuroCityEC and some special trains.