yeah, I used to fly London-San Francisco regularly. About 11 hour flight time. With hand luggage only, that came down to 16 hours door to door (based on hotel in Palo Alto or Menlo Park), of which 1h30 was travelling between home and London Heathrow.
The moment you need connecting flights is when you start racking up the extra time rapidly.
The moment you need connecting flights is when you start racking up the extra time rapidly.