A flight of wine is short for a tasting flight, loosely defined as a selection of wines, usually between three and eight glasses, but sometimes as many as fifty, for the purpose of sampling and comparison. In other words, its a lot of individual wines in small amounts.

I had to look this up also. :) It turns out the word "flight" is used in the same manner as "a flight of stairs". That is, the wines you taste are around the same level or, for larger selections, the tasting proceeds at the same level (start with lighter, simpler wines). As a result, you are able to compare wines of roughly equal quality instead of comparing a poorer wine to one superior. Anyway, this is my reference: http://winequestions.blogspot.com.au/2006/02/origin-of-flight-of-wines.html

Don't worry, most native English speakers don't know what a "flight of wine" is, either.