Day trip to Vienna by bus.  Slovak Line bus from Bratislava bus station to Vienna took about 90 minutes on a comfortable air conditioned bus.   The cost of the return trip for two adults and a teenager was E41.50.  Lots of traffic congestion in Vienna so a bit of a slow drag in and out of the city.   Bus station in Vienna is next to an underground station with travel information centre with English speaking staff.  Day tickets for public transport in Vienna are available.   Good option for a day trip to Vienna from Bratislava