There are two airports in Brussels, Brussels International Airport and Charleroi (Brussels South). There are many alternatives to fly from either of the airports. However, depending on your departure point, it might be more economical to fly to Paris (Charles De Gaulle), or Amsterdam (Schiphol) and then travel by train to Brussels.
A booklet containing information about traveling by airplane is available here.
Brussels airport (Zaventem) is the main international airport in Belgium. The airport is approximately 15km away from the venue location. You can reach the venue location by means of public transport and by taxi. For public transport you can plan your journey on STIB's journey planner by selecting "BRUSSELS AIRPORT" as Departure Stop and "BRUSSELS ROGIER" as Destination Stop. Taxi will cost around €20.
Charleroi airport (Brussels South) is a major hub for a number of low cost airlines. From Charleroi you can reach the venue location by means of public transport and by taxi. Shuttles between Charleroi and Brussels are cheap and frequent (Shuttles every 30min, one way ticket is 13 euros, travel time is about 1h30), find all information here.
Paris airport (Charles de Gaulle) is also a convenient possibility. You can take the high speed train from Charles De Gaulle to Brussels (85 min; Thalys; you have to book in advance). Of course, you can also take the «normal» direct trains (one train/hour; 120 min; 26 €). You can check the train connections, itineraries and prices at the website of the Belgian railways.
Amsterdam airport (Schiphol) is another convenient possibility to fly. You can take the train from Schiphol Airport to Brussels. You can take either the high speed trains (100 min; Thalys; you have to book in advance) or the «normal» direct trains (one train/hour; 120 min; 26 €). You can check the train connections, itineraries and prices at the website of the Belgian railways.