(To the post above)
I hear that after a characters focus is leveled up a bit, then flying wont cost a thing, even on the first level. Thats in XL2 but if you mean 1, then it's pretty handy at times. Once you level up a bit then it won't cost much on highest upgrade. Your focus bar will actually recharge faster than the points your flight takes off it. It's much faster than walking, and you can reach certain areas. Also useful for carrying team mates across big gaps.