The best flights from San Francisco to London

These overnight flights will be easier to sleep through. Your body clock will still be on your San Francisco timezone, so getting to sleep will be easier for flights after 7pm. By the time dinner is cleared away, it will be about 9pm and you'll feel naturally tired.

The second big benefit is that the flights will land nearer a time you would typically wake up in San Francisco. Your body will have had more chance to rest and recharge without interruption at a somewhat normal time. Earlier flights will leave you sleep deprived. Remember, you'll typically be offered breakfast 1-2 hours before landing too. That will feel easier nearer 6-7am on your body clock than 1-2 am.

If you do have to take an earlier flight, see if you can get the earliest possible flight then get home or to a hotel for a "proper" sleep until lunchtime in London the day you land (your body will want to this anyway). If you can land around dawn, get out the airport quickly, and beat the morning rush hour traffic home, this also works. Your flight then isn't so critical for sleep.

You might be too awake to go to bed in the new local time. Even if you haven't slept well inflight, your body clock will be on morning time in your San Francisco timezone. It's easier if you have more hours in London to adjust and tire out again before bed. If not, you may struggle to get to sleep again on the first night that you land, so your day 2 jetlag will become much worse.

If you do have to take these later flights, try not to sleep all the way through. Instead, try waking up about halfway through the flight and "starting your day" on London time. It won't feel easy, but you'll be more ready to click into the new timezone on arrival.

United have a lunchtime flight from San Francisco that lands around 7am. Although this gives a full day in London, 7am London time is still 11pm the previous day in California.

Your body's circadian rhythms will have had no reason to adjust, but the UK timezone means you'll need to stay awake for the full day.

If you do sleep after arrival, you'll likely be sleeping in a proper bed, much more deeply than on a plane. This is much harder to wake yourself from.

The exception is if you're on a very short trip from the UK and if you stay on (or near enough to) UK timezones. But even then, the breakfast service on this flight will be around 5:30am UK time.

Do your body clock a favour and avoid this crazy flight.

The current British Airways A380 layout has Economy split over the main and upper deck. Unlike the main deck 3-4-3 layout, the upper deck is 2-4-2 and has large side bins for storing your personal belongings (as opposed to just the overhead lockers).

Smaller cabins and easier aisle access feels far less crowded than the dense Economy cabins on other aircraft.

British Airways are reconfiguring their A380s at the moment. This will convert the entire upper deck to Club Suite, moving Premium Economy downstairs into a 2-4-2 configuration, and expanding from 55 to 84 seats. Economy will only be downstairs in a 3-4-3.

Virgin Atlantic's A330neos feature their best hard products in every cabin. Even in Economy, it is a markedly better product with plenty of twin seats thanks to the 2-4-2 configuration. That's great for couples and groups. Solo travellers have fewer 'strangers' to navigate. There's easiest aisle access for window seat lovers. Huge screens, bluetooth for your own headphones, and deep recline.

Premium Economy comes in a 2-3-2 setup.

Business Class gets the latest Upper Class Suite with forward-facing suites with doors and aisle-access. These give the best setup for sleep, work, and window-gazing. You can also book extra space in their new 'Retreat Suite' as an individual or couple.

Virgin's oldest Upper Class cabin divides fans. The design was first offered in 2003. You'll have the same onboard service, but the seat design is much narrower, angled towards the aisle with less privacy and little storage compared to modern configurations. Window gazers will find it frustrating trying to look out at a narrow angle while facing towards the middle of the cabin.

All the seats have aisle access, and these beds benefit from no obstruction to your feet so they're good for sleeping. These are also the only remaining aircraft with the onboard bar. The A330-300s will be out of the fleet by 2028, and the last 787-9 will be reconfigured by 2030.

Until then, you may get more for your money by booking an alternative cabin - either another Virgin flight, or an alternative airline with a more modern business class configuration.

Studies show the effects of lower cabin altitude (more oxygen and humidity) help with feeling less fatigued when you land.

787s, A350s and A380s have lower cabin altitudes than other aircraft. On long flights, like from London to San Francisco, you'll notice your skin, mouth, and nose dry through the flight.

Three major airports serve the San Francisco Bay Area. Even if you're travelling into the city, they are all competitive on door-to-door times. Search all of them to find a better deal.

There used to be direct flights to all three airports from London, but now they are all consolidated into SFO. That said, you can connect through to any of them from other gateway hubs in the USA. If direct LHR-SFO prices are high and you're considering one-stop flights anyway, see if you can save more by searching to all the Bay Area airports.

The longest US flights get a second hot meal service, but you'll have 7-8 hours between service where you can go hungry. There are snacks onboard, but they tend to be carb-heavy that can spike your blood sugar and not really fill you up. Other airlines pace their meal service better for long dayflights that might leave you wanting more.

Avoid grazing through the flight, and consider high-protein snacks. These do a better job making you feel full and trigger hormones that make you feel more alert. Carb-heavy snacks will send you on a blood sugar rollercoaster that might make you feel less with it when you land.