There are no direct flights, but you can fly via PRG (or BUD outside Skyteam).
For your dates, CSA will sell you a through ticket for 467 Euros, which may not be cheap, but it's still infinitely better than a bus. MA is cheaper, but still not cheap (EUR343).

If I were you, and given that you are returning to SOF, I would also think about renting a car. I'm pretty sure Sixt will allow you to take the car abroad (as long as you return it to where you rented it from).