Scroll through the results for cheap flights to Klagenfurt in Austria. To get the best deal, we'd advise booking in advance, particularly if you want to fly with a specific airline. Check your dates and see.
If these flights are too expensive, try searching for a different time of year. So if your dates are flexible, consider looking at different times of year.
So, if the flights to Klagenfurt don't work for you, you could always try searching for flights to other airports in Austria.
Looking at a few different departure airports will give you even more choice. See what you can find. And remember, it's best to book your flights in advance wherever possible.