Holding down the jump key allows Pharah to hover, gaining a small amount of altitude. A fuel meter will appear next to the crosshair while in use. It takes two seconds to deplete all fuel and two seconds of disuse to refill. Pharah is more mobile in flight, as she can access higher points and activate Barrage in mid-flight. This could easily make for an easy area clearing while her Concussive Blast is cooling down