Can A be capitalized in advertising language? Is it omitted in the subjunctive mood?

You should notice that the first letter of every word is capitalized (A has only one letter), and your understanding is correct, just for emphasis and prominence.

That can be omitted, usually in subjunctive mood, which is more written/formal.

For example, I

hope

(that)

I

can

fly

Do not put quotation marks in the title.