Since Qantas ditched Sydney-San Francisco flights, United Airlines offfers the only direct service between the two cities, as well as being another option from Sydney and Melbourne to Los Angeles.
We've reviewed United's business class to San Francisco, so now here's our expert guide to the flight's best business class seats – and the seats you should avoid if you can.
United flies a Boeing 747-400 on its routes to Australia, from Sydney and Melbourne to Los Angeles (LAX) and from Sydney to San Francisco (SFO).
The airline has 24 Boeing 747 aircraft in its fleet, with First, Business, Economy Plus (which is Economy with extra legroom) and Economy classes on the plane.
The Business Class cabin
The 52 Business Class seats are found on the lower deck (rows 6-10) with a 2-4-2 layout, and upstairs (rows 12-17) with a more cosy 2-2 seat configuration.
The seats are in a forward-and-back pattern, although it's not head-to-toe like British Airways' Club World business class. On United, each seat faces the same direction as the seat next to it, and is either head-to-head or toe-to-toe with the row in front and behind.
While some passengers don't like flying backwards, there's really no noticeable difference once you're in the air.
The seats themselves are 19 inches wide in seat mode and 23.5 inches wide in bed mode, including the arm rest (compare that with Qantas' business class at 21 inches).
There's more length when the seat is in bed form downstairs than upstairs -- up to 78 inches on the lower deck and 74 inches on the upper deck. The seat slides down into a fully flat bed which tapers slightly at the feet into a small footwell cubby-hole.
A 15.6-inch screen is well above average in class, with a on-demand entertainment system and an AC power point for laptops and other electronic devices. The power point will take Australian, US and Euro-style plugs, and there's a USB port for charging portable electronics.
For full details of the seat, cabin and service, take a look at our in-depth review of flight UA870 from Sydney to San Francisco.
The smaller upstairs cabin holds just 20 seats and has a very private-jet feel to it. Every seat is either a window or an aisle, and the window seats have an extra storage bin by the side.
Downstairs is significantly busier, since it's in a 2-4-2 layout for the most part. (2-4-2 means that A and B seats are by the left windows, then an aisle, CDGH seats in the middle, another aisle, and K seats by the windows on the right hand side.)
Rows 9 and 10 downstairs don't have a middle section (they're separated by the galley kitchen instead), and are further back in the cabin.
The best seats on the plane
Our pick on a 747 in business class is usually the upper deck (except for airlines like Virgin Atlantic and Air New Zealand, which have business class in the nose downstairs). United's 747s are no exception here.
15A 15K 16A 16K: these window seats towards the rear of the upstairs cabin have extra storage room in the side bins and are reasonably far away from noise and light sources like the galley kitchens and lavatories. The back of the upper deck has less background noise from passing air than the rest of the upper deck or the downstairs cabin. Row 15 may be chillier because of the exit doors just in front of it, though.
14A 14B 14J 14K: also upstairs, these seats are just in front of the exit row doors, meaning they may be chilly but are still a good distance from noise and light from the galley kitchens and lavatories.
7A 7B 7J 7K: if you do end up downstairs, try for the outer pairs in row 7, which are likely to be the quietest of the lot.
However, travellers significantly over six feet tall should aim the downstairs cabin, where certain seats extend to a full 78 inches of bed length:
- all of Row 6
- seats 7B, 7C, 7H, 7J
- seats 8B, 8D, 8G, 8H
- seats 9B, 9J
- seats 10B, 10J
The worst seats on the plane
Avoid the downstairs cabin if you can -- it's not as private, and is surrounded by galleys and lavatories. The one exception is for particularly tall passengers, who will benefit from a few inches of extra legroom in the footwell cubby hole.
Seats D and G: these middle seats have all the drawbacks of sitting next to the window (having to climb over someone to get out) but none of the benefits (being able to look out of the window). Avoid.
Row 9 and 10: you'd have thought that the two rows of pairs at the back of the Business Class cabin downstairs might be quieter, but they're right next to the galley kitchens and stairs to the upper deck, and economy plus is immediately behind them, leading to more noise and potential disturbance.
Row 6 and 8: these are next to the lavatories, and row 6 is next to the main first and business class galley kitchens as well.
Also in our Best Seats series: