Question : What day in the next four weeks has the best fares?
Answer : Since low prices are preferred, look at Apr 27th. As of Apr 17th, it's showing the cheapest ticket sales at $677. That is 61% below the average price for this route, so you can spend that extra cash on an adventure in Vienna.
Question : Are you paying the cheapest or highest price for your ticket to Vienna?
Answer : Flight prices change a lot more than most routes from the United States for BUF to VIE. They vary anywhere from $677 to $4,305. However, the sooner you book, the better price you tend to get.
Question : How long do most people stay in Vienna?
Answer : Of course you're not most people, but if you were, you'd stay roughly one week.
Question : Is price more important than specific travel days for you?
Answer : Tuesday is your lowest-cost day to fly in the month of May. Flexibility is paramount when booking travel plans in order to keep travel costs down.