My son and his grandmother will be flying American Airlines LAX to Berlin, with a 4 hour layover in London.
Is there enough time to grab a cab and do a quick ride around London, perhaps seeing only one attraction?
I'm thinking they'd have to go through customs in London, taking up even more time. Should they not even try it?
Not likely. 4 hours is a long time to sit and wait, but comparatively short when dealing with international customs and international security.
I, personally, wouldn't try it with a 4 hour window.
(And... in fact... had about 5 hours on my last connection there... opted to damage my bank account in duty free shops... maybe I'd been better off risking missing my connection...)
No, four hours absolutely will not work. Even six hours would be pushing it.
Your son and his grandmother might have time to take a taxi to Windsor (about 20 minutes from LHR) and back.
I wouldn't leave the airport unless it was a quick trip to Windsor. It's an hour into the city and an hour back - and you are supposed to be at the airport two hours before your ongoing flight. At BEST that would leave you an hour, and you would most likely get caught in traffic.
A good rule of thumb for Heathrow... look at your scheduled arrival time and add 30 minutes. Then add an hour to de-plane, pass through immigration control and get to the next terminal. Your 4 hour window is probably closer to two and half. Barely even enough time to get to Windsor and back, and London is right out.
