As much as I loved the banshee in the Halo games, Destiny just isn't made for air vehicles. The maps for the most part are designed for ground vehicles and infantry to have to stay on the ground, and follow paths made for them to reach their destination. Air vehicles would eliminate the adventure of those areas, and just fly right over everything. Not to mention, this would make the map feel a lot smaller. However, certain locations could support aircraft, and allow Guardians to have dogfights with the Fallen within the boundaries of specific areas. I would hope if Bungie were to do this they would make it realistic (For example: instead of "RETURN TO THE BATTLEFIELD...10...9...8.... They could make a storm that would cause ships to crash, or maybe some Vex antiaircraft guns. Anyways, that's just my input.