You've made some observations:
- You don't get certain assignments which you think are important
- You aren't involved in the interview process
- You feel your opinion is often ignored
From these observations, you're drawing a conclusion about whether or not the CTO likes you. While the observations are very real to you, the conclusion you've drawn may exist only in your head. So, if this is bothering you enough to make you want to do something, it makes the most sense to address the real things, not the imaginary things.
Work assignment, involvement in interviews, and weight given to various opinions are all sometimes challenging things for any manager. Before assuming that you're getting the raw end of the deal, it may make sense to bring these points up in a more generic, less directed manner.
So, you definitely don't want to say,
Hey boss, does the CTO hate me?
but you may also not want to say,
Why aren't I involved in interviews?
Instead, you could ask,
Hey boss, can you explain to me how the company chooses who to involve in interviews?
By doing this, you avoid any hint of an accusatory or defensive perception - and you may get a very direct answer to your question. Maybe the company chooses interviewers based on seniority, or some other characteristic that doesn't apply to you. Once your boss has responded, you can let him know if you're interested, or ask how you can become more involved, as appropriate.
Keep in mind though, that jumping to conclusions can be dangerous. Don't assume someone doesn't like you when there may be perfectly legitimate reasons for the behaviors you're seeing.