Anyone who has flown between London and New York knows the return is quicker. The distance is the same in both directions, roughly 3,000 nautical miles between the London business airports and Teterboro, yet a westbound private flight typically takes 7 h 30 to 8 h 30, and the eastbound one usually about an hour less. The difference is wind, and on a private jet it shapes far more than the arrival time.
A river of air at cruising height
Over the North Atlantic, the prevailing winds at the altitudes where jets cruise blow from west to east. They are concentrated in the jet stream, a band of fast-moving air that meanders across the ocean and is usually strongest in winter, when speeds in its core are often well over 100 knots. Eastbound flights try to ride it. Westbound flights try to avoid the worst of it, but over a crossing of seven or eight hours they still spend much of the time pushing against a headwind.
Every day, oceanic air traffic services publish a set of routes across the ocean that take account of the winds. Flight planners pick the one that gives the best result for the day, which can mean flying a longer path to dodge the strongest headwind. Either way, the aircraft's speed over the ground is lower westbound than its speed through the air.
What the wind does to time
The table shows the effect in round numbers for a 3,000 nautical mile crossing at a cruise speed of 450 knots, with about 30 minutes added for climb, descent and routing. It is an illustration rather than a flight plan, but it shows the pattern.
| Average wind | Westbound time | Eastbound time | Range used westbound (still-air equivalent) |
|---|---|---|---|
| Calm | about 7 h 10 | about 7 h 10 | 3,000 nm |
| 40 knots | about 7 h 50 | about 6 h 40 | about 3,290 nm |
| 70 knots | about 8 h 25 | about 6 h 15 | about 3,550 nm |
| 100 knots | about 9 h 05 | about 5 h 55 | about 3,860 nm |
The last column is the one that matters for aircraft choice. Against an average 70-knot headwind, the aircraft burns fuel as if it were flying more than 3,500 nautical miles in still air, before any reserves are added. Those reserves are not optional: the operator must carry enough fuel to reach an alternate airport and hold if the weather at the destination closes in.
Why range figures need care
Aircraft range is usually quoted for a particular payload, typically a few passengers, with standard reserves and no wind. Add more passengers and bags and the maximum fuel the aircraft can carry may fall, and with it the range. Add a winter headwind and the usable distance shrinks again. That is why an aircraft advertised at 3,500 nautical miles may cross eastbound with ease and still need a stop westbound in January.
In practice, the categories sort themselves out like this:
- Ultra long range jets, with 7,500 nautical miles or more, cross in either direction with a large margin.
- Large cabin jets, with around 4,000 to 4,300 nautical miles, fly westbound nonstop on most days, including most winter days.
- Super-midsize jets, at 3,200 to 4,000 nautical miles, span the boundary. Longer-range models often go nonstop westbound with a light load; shorter-range ones plan a stop, more often in winter.
- Midsize jets and smaller cross only with stops, usually two westbound.
Seasons and timing
Because the jet stream is generally stronger in winter, the westbound crossing is hardest from roughly November to March. Summer winds are usually gentler, which is when more super-midsize aircraft manage the westbound trip nonstop. The day matters too: winds shift from one day to the next, and an operator will often confirm a nonstop plan only once the forecast for your departure is known.
Westbound flights also gain time on the clock. New York is normally five hours behind London, so a mid-morning departure from Farnborough reaches Teterboro around lunchtime local time. Eastbound, the clock works against you: leave New York in the evening and you land in London the next morning, which makes a flat seat or a divan worth considering on the return.
None of this makes the westbound crossing unusual or difficult for a well-equipped operator. It is simply the reason flight plans on this route are built around the day's winds rather than a fixed timetable, and why a sensible plan always carries a margin.
What this means when you book
Three practical points follow. First, choose the aircraft for the westbound leg, since it is the harder one; an aircraft that only just manages it leaves little room for a full cabin or a strong winter wind. Second, ask whether the plan is nonstop or includes a technical stop, and what would change it on the day. Third, if a stop is likely, consider whether a larger aircraft at a higher hourly rate actually costs much more once the extra hour and the landing fees are counted.
Choose the jet for the westbound leg. The eastbound flight will take care of itself.
We plan this with the operator before any option reaches you. Each quote states whether the westbound flight is planned nonstop or with a stop, with the time and an all-in price, so you can compare a larger aircraft flying straight through with a smaller one that pauses on the way. Try the combinations yourself in the crossing guide.