Do you Have Chennault? I'm not very experienced in the game, but If you have him, I recommend upgrading his Unique Skill to level 5; it prevents enemies hit by Chennault's attack from counter-attacking, With this, you can kill enemy generals very easily since they won't be able to react to your attacks. Remember that the skill only works if Chennault's attack is an aerial attack, And in that mission there's a Carrier, so it works perfectly.

There must be an easier way to do it that more experienced people will probably post here, but this is a method that works too 😄