Budapest 
in $2400s-$2600s RT
OliviaJFC
You get a lot of bang for your buck with Budapest, because it's really two cities in one.
Buda, west of the Danube, is the storybook side of the city. This is where you'll find the eye-catching medieval architecture, that fairytale-esque castle, and plenty of winding woodland nature trails.
Pest, across the river, is where the city's action happens. Trendy cafés, museums, markets, and that almost-vampiric-looking Parliament are all on this side, as well as all those gritty, artsy, ruin bars.
And pálinka? Hungary's favorite fruity spirit? That you'll be able to find just about anywhere :-)
Jack's take
We always love a good business class fare to Europe, especially for those less obvious destinations. Air Serbia isn't the flashiest airline, but it might surprise you.