Practice running away. Seriously, the hawk is amazing at running away. It's also amazing at decapping, since it can fly across the map to a point faster than you can redeploy. My other tip would be to save your shots for enemies that you can't get close to. If you can get behind them, they won't see you coming, so just backstab them. You'll kill them quicker, and save your ammo. Also, don't reload on the ground. You are slow and vulnerable on the ground, and your reload is slow as well. You can reload in the air while gliding. The last trick is to focus on accuracy mods, and take potshots at people's heads from high locations. You won't be a full blown sniper, but you can apply some serious pressure that way. Plays to the class's strengths, as it takes advantage of locations no one else can get to.
Your job as a Swooping Hawk at lvl 1 and no gear is denying Heavy Bolters from staying braced. You'll get kills if you hit them from odd angles like above and behind them. You can solo entire gun lines if they are distracted by something, and if they turn to face you, they're facing you, not your team. Use this creatively and watch the storm approach behind an entire team's back and laugh as they get cut down. Hawks are down right mean if you get enough practice flying around with them. If you happen to see a large amount of MYST in your game, communicate with them and you'll start to see the punishment. Likewise, if you see WoK, MYST, SWND, or WP as Hawks, follow them. They'll show you where you should be and 2 hawks working in tandom is just nasty.
View: https://www.youtube.com/watch?v=d5nRQy7tsKw Wellz Gotta say dat playin' dat Hawk boy iz actually fun
Swooping Hawks are, by far, the most enjoyable class in the game for me. It feels good to fly. For me, everything else is gravy. I will say that Swooping Hawk survivability is through the roof once you figure out the art of running away.
Once you figure out the art of *noping the f*** out of there. Fixed that for ya. ;D (Forgive me I couldn't resist)