Re: Yes/No Answer
It does not matter if the question was phrased in the positive or negative, really.
Yes, I am planning to. Yes, I was planning to. Yes, I do that. Yes, I did that. Yes, I will do that.
No, I am not planning to. No, I was not planning to. No, I don't do that. No, I never did that. No, I won'd to that.
If you want CLARITY in your communication, use a full sentence.
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.