well actually it would not take a whole lot of work to keep the missles positioned relative to the plane. It takes just as much work as to keep the camera behind the plane as it does to position the missles. All you need to do is position the missiles relavtive to the Plane.
1. Find Planes X,Y,Z
2. Subtract from the Y because you want the missiles under
3. Add to the X to get the missiles to the right of the plane.
4. Add or subract to the Z to get the missiles forward or back
<experiment to find the best position>
5. Position the Missiles in the position that you determined above. You need to do that once every loop so that missiles are allways positioned at the right place.
6. Rotate the Missiles (Point Object) to be the same as the planes.
I think that should do it, but im kinda too sleepy to test in DBP.
To do the crosshair one solution would be too paste an image in the middle of the screen that looks like a cross hair. Then create an object (small little cube) and hide it (hide object). In every loop position that object say 30 away from the plane. and at the same Y and X position. Then when the missiles shoot, just point the missile at the little hidden cube, and when the move forward (move object) they will automatically move towards the "crosshair".
Also if you do the above, you may want the missile to turn towards the crosshair instead of just launching and automatically be pointed at the crosshair. To do that use the Curve Angle comamnd. That way you can curve the angle of the missile towards the crosshair.
crosshairX,crosshairY,crosshairZ - Position of the hidden box.
missileX,missileY,MissileZ - Position of the missile
once the missile is launched :
NewX = Curveangle(crosshairX,missileX,13) - 13 is the speed.
NewY = Curveangle(crosshairY,missileY,13) - 13 is the speed.
NewZ = Curveangle(crosshairZ,missileZ,13) - 13 is the speed.
point object <missle's number>,NewX,NewY,NewZ
that will turn the missile towards the box as it flies.
Remember to experiment.
Hope that helps
around here.. normal's just a setting on a hair dryer