Now that I've found Chi, how do I convince him to join me

You first have to talk with him.

Do you remember Troy?

If not, you won't know what the conversation path is.  Try this:

1) You're out to rescue a girl.

3) Talk about military mismatches.

3) What about that wooden horse?

Now, how can you show him that planes are safe?

Seen anything that flies?

How about a flier?