A trailer from BioShock Infinite that seems to have been released about a week ago (thanks Eurogamer) features Ken Levine from Irrational Games explaining the role of Sky-Lines in the upcoming shooter sequel. These were built as a system to move cargo around on the floating city of Columbia, though Ken describes how they also began serving as transportation for people, originally mischievous kids, but later by most of Columbia's populace, as they still needed to get around once the situation in the city began to deteriorate. This lead to them being used for "all kinds of purposes, including, and especially, combat." Ken describes how this adds the ability to experience the game's airborne environment in combat, as opposed to the watery environment of the first BioShock, which he describes as "really just a piece of art: We never really dealt with, you know, what it was like to fight at the bottom of the ocean in any meaningful way." The embedded trailer follows.