Depends on the mechanism used by the missile to follow the target. My impression is that most missiles don't have guidance systems that require direct communication after launch,
A whole bunch of missiles actually do, like the Sparrow and Standard.
The longer range ones really can use it to increase hit probability. Or so I've read is true for the Phoenix and AIM-120 missiles, classed as "fire and forget". and the newest Standard missile uses a AIM-120 derived head with a bigger antenna. And I'm sure still depends on mid-course corrections (for that matter, I've read the current models self-destruct if they doesn't get guidance fairly soon after launch).
The Sparrow and Standard are "semi-active radar homing missiles", meaning that they have a radar seeker head and no emitter. They require an external illumination radar (from the aircraft or launch platform) to light up their target.
The AIM-120 uses a datalink to guide the missile close to the target, after which the missile's internal radar emitter goes active, and the missile locks onto the nearest target that it finds. This is because the radar on the missile is not nearly as powerful as the radar on the aircraft. So it's not truly a "fire and forget" missile, at least if a high probability of kill is desired. I believe the Phoenix is similar.
Per what I've read elsewhere, and the Wikipedia article (https://en.wikipedia.org/wiki/Phoenix_missile), for long range attack the Phoenix has a rather unique flight profile, it climbs to 80,000 or so feet and cruises there, then dives down. Per the article, at 11 miles it activates its radar, and I'll bet given the distance and its bigger size, bigger antenna, it gets a bigger view than the AIM-120. Still, it has the capability of and uses course corrections from its plane.
I believe the Phoenix usually falls off its plane (the F-14) directly into the ocean. The Tomcat pilots then RTB to the bar and tell each other how great they are. The Phoenix is the Yugo to the AMMRAM's Ferrari. They are different generations of weapons.
Nope. Missiles are usually fire-and-forget. They are autonomous. Can you ram their radar? Maybe, but many have visual and heat sensors as well. If you want to see something scary today:
https://www.youtube.com/watch?v=Fcx8Xke9It4
Fire-and-forget does not mean that you can just launch a missile and it will do its own thing. The missile still needs to be guided to the general vicinity of the target before it can do its job.
