If you want to take the ‘fastest’ travel option, you often choose a flight.
Think about the total amount of time you’ll be on the road. The time going to the airport / waiting for the flight / flying / going to Ghent from the airport. Often it takes as long as travelling by train within a range of 1000km. Just saying 😉
If you want to go for the cheapest travel option, take some time to compare the prices to those of trains or busses. Just asking.
You decide to come by plane?
Most cheap flights will end up in Charleroi (Brussels South Charleroi Airport), which is still a few hours away from Ghent. The biggest and main airport is Brussels National Airport Zaventem.
From any Belgian airport you can take a train to Ghent. Make sure the trains are (still) running if you arrive on a late night flight or you leave with an early flight. (more info see train).
From Brussels South Charleroi Airport you can also travel to Ghent by Flibco bus (which goes faster than the train). But you need to be lucky with the schedule.
Consider buying some carbon offset to compensate your travels. Thank you.