If arriving by plane, international travelers will fly into Brussels Airport in Zaventem. The airport receives flights from Europe and from all over the world. Some of the most popular destinations are: Madrid, Los Angeles, Mexico City, Bangkok, Prague, Hong Kong, New York and Miami among many other cities worldwide. For details about arriving and departing flights, check out the airport's website at: http://www.brusselsairport.be.

From the airport to Ghent, your best bet is to take the train. The service is efficient and frequent, several trains leave for Ghent per hour. For a complete schedule of departures, check out the Belgian Railways website at: http://www.b-rail.be (the website has a Dutch, French, English and German version). Online, you can search for trains and purchase your tickets. Two things to look out for when going by train:

1) Take a train to "Gent" (the Dutch way to write Ghent), not "Genk" (that's completely the other direction)

2) Check the timetables or ask which are the fast and slow trains. Ghent is served by quick trains that stop only in Brussels before reaching Ghent, but there are also local trains that stop more than 10 times and take much longer to get there. The quickest service might include changing trains in Brussels; you can do so in any Brussels station, but the nicest one is Brussels South station ("Brussel Zuid" in Dutch, "Bruxelles midi" in French).

From the railway station, you can board the tram or take a taxi to your destination in town. 

You can also rent a car at Brussels Airport. Major rental companies have booths on the premises (Avis, Budget, Europcar, Hertz, National, SIXT).