This is for anyone that decided to do their machine gun only run while playing in Normal mode. Nothing changes outside the norm for the mission where you destroy all the other ships. You get 2 planes down as fast as possible to call the anti support guys to kill off all the jets trying to kill you. It's the very end where all that's left is Aigaion cruiser is where the problem occurs..
When you play on normal, the spot to take it down the Aigaion changes compared to where it is on Hard and up.. While this is really isn't a problem if you're using missiles, it is a very big problem when you're doing your machine gun only run.
I'm sure you'll die on your 1st attempt of many at this, so at the checkpoint, call your anti-air support to kill the guns on the back of the ship. Then you want to fly up until you can level out on the front top of the plane. Best way to tell how to position yourself is to look for the light gray squares up at the front of the plane where the cockpit is. Get your plane between the left and right light gray squares and you will need to aim in front of the light gray one at the front of the plane to take it down.
Now here is the fun part. The Aigaion's draft will suck your jet down, so you can't just set still. Plus the missiles keep firing off from the top as well. So here is what you do to avoid those from killing you.
Once you get into position, high G it by pulling up, then do a slow 360 degree circle while flipping the plane over upside down. Once you're facing almost backwards, the missiles will start to target you, high G the rest of the circle and you should come down right back on top of the plane where the missiles will lose their target on you. Level yourself out as much as you can but angle your gun and shoot the whole time towards the tip of the nose above that light gray square at the front of the plane. Shoot as you're angling down, pull up a little, repeat until you get to close or the missiles are targeting you again. Now you repeat the above circle loop to avoid it all again. The closer you are to the front of the plane with the down angle to where you can see the tip of the nose on the plane is when you'll hit it. Once you hit it, you should hit it enough to take it out. If not, you'll like one "HIT" to show up on the screen and you'll be like, what did I hit.
By doing the above, you can avoid getting hit and keep trying to find that sweet spot to take the plane down. It took me about 30 minutes to figure this out and make it happen. Hopefully this will help someone out when you hit this mission while doing machine guns only.