how to make Enemy Ai aircraft shoot at me

you have to decide what he fires to you with, whether it is some rigidbody ballistics, or some lasers made from long cubes without collision, so basically you're just looking for simple Cannonball, laserbeam, bullet, firing scripts, and making him shooting you literally a few lines like-

if enemy/player distance smaller than 500 m AND enemy relative rotation to player smaller than 10 angles, activate enemy shooting.

the difficult part is the 2nd, you have to find the correct function for relative angle between 2 objects https://www.google.fr/search?q=unity+relative+angle+between+2+objects&oq=unity+relative+angle+between+2+objects&aqs=chrome..69i57j69i65j69i60l4.1390j0&sourceid=chrome&espv=2&es_sm=93&ie=UTF-8

start by making the enemy shoot constantly, and then try and learn to make for lines of conditions from position and angle

Now that is the problem because i have no idea how to make enemy ai shoot at me even constatly i made the ai shot but the bullets just stood still