Your first reaction was wrong and impolite.
That’s how desperate housewives (whom their husbands never touch) or old people who hate the world (for not dying along with them) act.
Your first reaction ought to be:
The next day, or some other day, in a time that is not inconvenient for your neighbor,
you should knock on his door, introduce yourself, and politely explain the problem.
Ask if there is a reason why he has to start the car at that time,
and suggest a way to solve the issue, or ask him to suggest a way.
If his reaction was positive… fine!
If his reaction was negative… you should insist politely,
and propose new ways to solve the dispute,
and again explain to him what is your problem,
and that you are willing to find a solution that suits you both.
If his reaction was again negative, you should repeat the above scenario, once more,
so it would become clear to him that this is important to you,
and that a solution must be found.
All of this is would be done, of course, because he is your neighbor,
and not some guy that just happened to pass by your neighborhood.
If reason failed, then you should have tried more “violent” means.
Talks that imply threats (but not direct threats).
In a semi-polite way., and certainly not in an aggressive tone.
So that he would understand that you are determined to take some action.
For example…
“If I had done that, instead of you, you would have called the police. Wouldn’t you?”
“How would you feel if I hit the horn every time I passed by your house?”
“What would you do if you were in my place?”
I guess you are, now, thinking of going with the “aggressive” mode, (although you missed the “polite” phase),
and “complete” the mess you have created.
If, on the other hand, you are trying to fix things, the only way I can think of is a “love attack”.
Even if the “love attack” fails, it would at least give you ground to imply the “polite approach” first,
and the “aggressive approach” later.
And finally, if you really mean it, realize some of these threats.
Good lack, and try putting yourself in your neighbors shoes, before acting, next time.