how early must I get to haneda?

I need to fly out of Haneda at 6:30am, but I've just realized that most public transport doesn't get to the airport until around 6ish. The airline says that you can show up 20 minutes beforehand, but I'm a little leery... Does anyone have any experience with taking the first flight of the day? Alternately, does anyone have any advice on how to get to the airport early in the morning? (the train, Airport Limo and Haneda Bus just get me a little bit too close for comfort)

Thanks.

I need to fly out of Haneda at 6:30am, but I've just realized that most public transport doesn't get to the airport until around 6ish.

You must have checked unreliable resources! Public transportation to the airport starts around 5am.

For domestic flights, you need to check until 15 minutes before departure and be at the gate until 10 minutes before departure. So, arriving at the airport by around 6am would be okay if you were familiar with the airport. But since you are not familiar with the airport, I recommend to be there by around 5:45, i.e. catch a monorail from Hamamatsucho or Keikyu train from Shinagawa around 5:20.

Alright! I'm from the States so running into the airport at the last minute is a definite no-no nowadays. I unfortunately don't live close to Shinagawa or Hamamatsucho, so it is good to know it's alright to cut it a little close.