Airlines are offering a wider-than-ever choice of non-stop long-haul flights, which save passengers the time and trouble of making connections. The latest route is United Airlines' 16-hour marathon between Chicago and Hong Kong.
But while direct flights are convenient, they do not lessen the adverse effects flying has on our bodies. Research shows that 75 per cent of frequent flyers find their performance affected on arrival, even after short cross time-zone flights.
The key to better survival on board lies in understanding what you are up against, both psychologically and physiologically, and then preparing yourself accordingly.
Some passengers find the prospect of being trapped in an aircraft for the greater part of a day daunting, and one of the main stress factors on board is the lack of personal space. So always spread out if you have the chance - flying premium class will give you more room and comfort, but you or your firm will pay for it.
Another technique, which is suggested by hotshot Washington DC lawyer Middleton Murray, is a ritual of familiarisation. This involves doing similar things throughout each journey, such as always travelling with the same airline, at the same time of day, reserving the same seat number and booking into the same hotel.
A novel way to spend the time is to undertake a creative project such as writing a speech or film script. Film director Robert Altman took up the challenge of turning a book of short stories by Raymond Carver into a movie during a 12-hour flight from Hollywood to Rome.
"I started reading his stories and falling asleep, then waking and reading a couple more," he says. By the time he had arrived, the stories had run together into a movie.
As the major physiological stress the body has to face in-flight is the lack of oxygen caused by the pressurised cabin, it is best to keep your activities low-key. Most passengers are unaware that the cabin altitude is an average of 8,000 feet, which represents 25 per cent less oxygen by pressure. The heart is put under strain to compensate, and even if passengers do nothing or sleep, they arrive extremely fatigued for several hours or days later.
One means of preventing oxygen loss in cells while on board is to drink carrot juice four days before departure, as well as on the day of the flight. Experiments have shown that carrots guard against oxygen deficiency, and their beta-carotene content helps prevent infections at low pressures.
The ultimate quick fix, of course, is a whiff of oxygen. But portable oxygen canisters contain at least one-and-a-half hour's worth, which could well send your headache or hangover packing too.
The best antidote to your long-haul flight is to oxygenate by taking a strenuous walk as soon as you land. It will also help expel toxins ingested from recycled air and petit fours.