Help with a question

Is it possible to board a plane in the United States that departs to another country?
Say for instance, a flight from California to Japan??
Could it be possible with all proper regulation followed (in other words, with a passport and immigration procedures followed for the country where your going)???

Thanks alot for any help. It is just a question that figures in my plans.

[*I'm undocumented, by the way]

As far as I know, the US does not really have you going through customs in order to get out (some other countries like Japan would do such a thing), and from my flight experience, international flights leave from the same terminals as domestic flights. (I almost made the mistake of getting on an international flights because my flight had changed gates last minute and I was running late to the plane). The country of destination will have their own version of customs, not sure what would happen, depends on them.

However, leaving the country will commence the mandatory ban, you will not be allowed to enter the country until the mandatory ban has been completed, and even then the chances of being allowed back into the country are very slim due to the undocumented status one had before.

I hope you are not planning on leaving {specially not for a stupid reason like vacationing, thinking you will be able to sneak back in without anyone noticing, it does not work that way}.

Yep. You can leave the country ... you just can't come back.