"Domestic flights in this country are a crime, they are a sin. You will not find, under a Johnson mayoralty, 381 officials taking flights within this country. That's absolutely criminal."
With recent revelations about Cameron failing to properly declare three domestic flights laid on by donors, this seemed to be sailing a little bit close to the wind.
But never mind that discrepancy. Boris was there to sell his green credentials and paint his vision for a greener London. So what was it?
He made it clear that he was against an expansion of Heathrow and that he had the perfect alternative:
Build another airport in the east.
Another successful day in the re-branding of Boris then.