Hourou No Plan Kikou

[Nisto]

Perhaps it should be "No Plan" with a capital n on the "No". To avoid confusion between kana "no" and the english word "No".

[Hellacia]

If it's not written in English in lowercase and we're doing a proper capitalization translation from English, then yeah, the word "no" is capitalized in titles, always. It's never a part of speech that you would lowercase.

EDIT: Okay, if this is meant to be the English word "no", capitalize it. If it's meant to be the Japanese word "no", lowercase it. They used the kana "no" like you said so I'm assuming they mean the English word?

[Nisto]

ノー is the English word "No" (note the ー).
ノ (which is a less used variation of hiragana の) is the Japanese particle "no" (as we usually write it; in small letters only).

[Hellacia]

Yeah, okay, so good one on the caps buddy