Flight search engine company Hipmunk has raised $5.9 million in funding according to an SEC filing. Hipmunk was co-founded by Adam Goldstein and Steve Huffman this past August. Huffman is a co-founder in Reddit. Hipmunk is known for laying out flight information in a customizable grid after conducting a search. Hipmunk has raised a total of $4.7 million in funding. The company was incubated by Y Combinator and they have raised a $1 million angel round from Ashton Kutcher, Paul Buchheit, Matt Mullenweg, Ron Conway, etc. The investors in this round was undisclosed.