PageRank is an algorithm popularized by the Google Search Engine and created by Larry Page. Ian Rogers says (see http://www.cs.princeton.edu/~chazelle/courses/BIB/pagerank.htm):
"(...)PageRank is a “vote”, by all the other pages on the Web, about how important a page is. A link to a page counts as a vote of support. If there’s no link there’s no support (but it’s an abstention from voting rather than a vote against the page)."
As you might imagine, this method can be applied to other problems and not only to ranking web pages. In our context, we can use it to determine airport ranking. To achieve this, we can use the number of flights and connections to and from various airports included that are in this departure delay dataset.