How to address the VP of a company or department? I have been told that addressing by name was not polite.
Unless you knew him personally, it would certainly not be appropriate in the UK, and I imagine it would not be in the US either. Few men will object to being addressed by a stranger as 'Dear Sir'.
"Sir" means "a respectful or formal term of address used to a man". Omit it, and you also omit respect. You use "Dear [name]" if the person you are addressing to is close to you.
If you are writing a business-related letter, do not omit "Sir" even if the CEO is your husband!