All major middle eastern and European airways have connecting flights to Budapest. You can also take the new Air India direct flight to Vienna from New Delhi and then reach Budapest by either rail/bus/cab/waterways.
Many European and North American Airlines fly directly to the Budapest Liszt Ferenc International Airport or offer connections. There is only one terminal: T2. All major rental car companies have their offices in the arrival hall of the airport. A taxi might be a little pricey, but is a convenient option. The airport mini bus is a far more cheaper and popular option of getting from the airport to the main city. The airport public bus number 200E takes you to a metro station, from where the metro takes the passengers straight to the main city.
Budapest has a good connection by roads. Getting to Budapest by a car would be pretty feasible if you have one or if you want to rent out a car. For using the motorways you have to buy a motorway sticker: M1, M3, M5, M6 and M7 (available at border crossing points and at petrol stations). Wearing seatbelt is mandatory both in front and rear seats. Driving after consumption of any alcohol will lead to driver's licence being confiscated on the spot.
There are 3 major international railway stations in Budapest. The train frequency is excellent between Budapest and its neighbouring cities such as Vienna. The international railway stations connect Budapest directly to 25 other European capital cities. Austrian Railjet is easily one of the best ways to travel to and fro Budapest via rail. There are choices between sleeper and seater trains. The seater trains are preferred for shorter travel distances. The reservation to these trains may or may not be mandatory. You can book your seats www.mavcsoport.hu , the tickets need to be collected from the little blue internet collection machines or the larger yellow ticket vending machines at Budapest Keleti and other main Hungarian stations. You can also use www.oebb.at for ticket reservations, which provide print at home tickets. It is a little more pricy to book tickets from here.
There are more than a couple of bus stations, the international and domestic buses depart from and arrive to the N_pliget Bus Station. There are a variety of bus companies that provide to and fro bus travel from Budapest to other countries like Austria, Belgium, Bulgaria, Croatia, Czech Republic, Spain, Sweden, etc. www.busradar.com and www.checkmybus.com are sites to help in online reservation of buses and also choose from the variety of bus services according popularity and pricing. If you are staying at a hostel and are on a budget trip, make sure to ask the people at the hostel desk for bus and travel suggestions.
A speedboat service is available from Budapest to Vienna between June and September. It takes you through scenic areas of Hungary (such as the beautiful Danube Bend), after which you arrive in the heart of Budapest.
+ 48photos