Ideas
I usually fly helis and sometimes jets and have faced both these issues. Only the warning that my heli or jet is painted and no warning for the coming tow missile. Also after the missile is launched even if somehow I manage to dive behind a mountain, breaking line of site at the last seconds, the missile will still hit 100 percent of the time.
While no warning and countermeasures not working might make sense with the way these weapons work, they do break the balance between especially helis and tanks. I had a game where enemy's team had figured this out. The enemy tank was just sitting in or very near their own spawn/HQ and each time I flew past our teams mountain and gained only a bit of altitude, I got painted, towed, the end and there was no saving the heli with diving down fast behind the mountain or counter measured after the paint warning and seconds before the tank hit with the stupid lock on. Note that this can happen so quickly that you might not even get a kill or just one or two nearby enemy enfantry if the enemy team knows about this dirty bug/feature and is dedicated to doing this to all helis. Also note this was the big open map that has only two mountains on either side of the map, each one near one of the teams HQ and a small refinery in between. Most of the map is flat and there is very few places to hide anyways. Also you cant be flying too low the whole time never gaining any altitutde in general ( even in maps with more cover) as every engineer and their mom will be carrying RPGs and AA launchers and tanks can easily shoot you down in one shot even. My point here is since specifically helis like some other vehicles in the game are glass canons, flying low all the time to break the laser line of sight will be a bit too deadly if you can never gain altitude with the heli (flying high=you get painted= sure death).
This target designation and tow missile also existed in the previous game BF2042 but being painted and a tow launched at you didnt equal certain death for helis or even jets like it does here. I have reverted back to mopstly playing BF 2042 now. I like BF6 graphics and most of the design but this one thing is ruining the biggest pleasure (flying esp. helis) for me. Pleeease fix this.