As far as I have tested aircrafts never cloak

Only with veteran and elite abilities.
Ad5) I think that deathweapon is needed, because I have once made a drone based on Hornet and removed DeathWeapon. When it was shot down, it didn't reach land and caused IE. When I have added HornetCollision (correct me if I made mistake in spelling) the IE no longer appeared however it's primary weapon was MagneticBeam so I am not 100% sure about that.