If department stores are the cathedrals of commerce, Christmas windows are the stained glass that lifts the spirits of the faithful. Months in the planning, the displays being unveiled in department stores and chic boutiques this week have more in common with installations in the Tate Modern’s Turbine Hall, than they do with tacky seasonal decorations. It is no exaggeration to say that some of these displays are ephemeral works of art: after all, both Andy Warhol and Jasper Johns counted window dressing among their early works. Concepts rule; selling clothes is secondary.

In the windows of Louis Vuitton’s flagship store on Bond Street, monogrammed handbags in jewel colours sit atop contoured poplar wood. At a push, the pale wood could be said to resemble snowy mountains, but nothing about the installation says Christmas kitsch. Like a bona-fide art exhibit, the construction even has its own name: Latitude 48.914/Longitude 02.286, which refers to the exact location of the brand’s original workshop in Asniиres, France.

Such lofty artiness is no accident, since the windows are the result of a competition open to design students at Central St Martins college. The winning design, by Christopher Lawson and Marcos Villalba, which will be shown in every one of Louis Vuitton’s 382 stores worldwide, strikes the consummate balance between high-art concept and shop window. Made from the same wood as the framework of Louis Vuitton’s signature trunks, the installation reproduces the contours of a topographic map to create an abstract landscape, while simultaneously providing handy shelves for 1,000 bags.

Yves Carcelle, the suave CEO of Louis Vuitton, explains that he was “intellectually seduced” by the concept. He believes that a successful window display is, “an invitation to the party” - albeit in this case, one at which your credit card will suffer.

Lawson and Villalba are not the first artists to find themselves window dressing. In previous years, Robert Wilson and Takashi Murakami have expressed their ideas in Louis Vuitton’s windows. In New York in 1961, Andy Warhol designed the windows for the department store Lord & Taylor, installing his giant paintings of Dick Tracy behind the glass. Other 60s pop artists followed suit - Robert Rauschenberg, Jim Dine and Jasper Johns were all involved with Christmas displays for the store.

Conceptual window displays were not new, even in the 1960s. In 1901, the New York Times was reporting that a scarf shown out of context in the window of a department store in Philadelphia had caused a “sensation”. The reporter noted that the aim of a successful display was “to hold up the passing pedestrian in the street”. Which is pretty much the aim of today’s window dressers.

Linda Hewson is the creative manager and display supremo at Selfridges. She describes the store’s surreal and heavily bejewelled window creations unveiled this week as being “somewhere between Narnia and Lost” and believes that her displays are much more about visual impact than selling. Jewel-encrusted satellite dishes and telephone boxes sit in strange cityscapes alongside glam-rock mannequins behind the store’s Oxford Street windows. “They aren’t meant to sell actual products, they’re meant to pull people into the store. Our windows are like the front cover of a magazine - they show the zeitgeist. It’s about a feeling” she explains, “and sometimes we do it without any product at all.” In 1994, rival store Harvey Nichols took this to the extreme, cancelling its Christmas windows with a notice that stated that the display budget had been donated to charity instead. Alas, they didn’t let on exactly how much that was.

Simon Doonan, the maverick window dresser for the prestigious department store Barneys, in New York, and bestselling author of Confessions of a Window Dresser, is often cited as being instrumental in blurring the line between art and commerce in window dressing. Born in Reading in 1952, he went to work in London, and by the mid 70s he had honed what was to become his signature irreverent style. A display of tuxedos posing around rubbish bins surrounded by scampering rhinestone-wearing rats might not seem shocking now, but 30 years ago it was enough to attract the attention of the owner of Maxfield department store in Los Angeles. Soon afterwards he began working at Barneys and was inviting artists such as Jean-Michel Basquiat and Julian Schnabel to collaborate with him.

Unsurprisingly, in an industry that depends on them, fashion’s window displays aren’t immune to trends. This year there is a return to some traditional themes, but with a conceptual twist none the less. According to Neil Ellis of PLANarama, which looks after many of the high-street windows, including Marks and Spencer’s, people like Christmas cliches: it’s how those cliches are interpreted that counts. This year, Christmas trees are back, but they have been wrapped in acetate at Gieves and Hawkes (inspired by a Parisian street furniture exhibition) and dyed pastel at Harvey Nichols. (Red, green and white were judged to be the wrong side of traditional.) Meanwhile, gigantic interlocked paper-chains weave in and out of the windows at Jaeger.

Just like works of art, a good window display can reveal lots about the year it was conceived. Take this year’s effort at Harvey Nichols, where polar bears and deer stand around amid snowy surroundings. According to Janet Wardley, visual merchandising controller at the store, global warming has “elevated snow to luxury status”. It’s scarcer, ergo it’s desirable.

But ultimately, it will be hard to judge the success of these elaborate window displays. The number of shoppers stopping to take snaps on their mobile phones provides a rough guide, but there is no way of counting how many people will have been seduced by them. Nor are the displays ever likely to be seen in situ again. Carcelle and the people at Louis Vuitton intend to recycle as much of the wood as they can but, come sale-time, most of the carefully conceived displays will be left to gather dust in a stockroom. Not that the creative teams seem to mind too much. “It’s disposable art,” says Ellis, “it looks great for six weeks, but then it goes in the bin.”

As a general rule, this column does not dispense advice. The rule is temporarily suspended. Here is some advice for business travelers:

Expect to be spending more weekends away from home.

Plan travel as far ahead as possible, but read the fine print on your airplane ticket.

Do not pay for an airline ticket with anything but a credit card.

Make the best of your time at the airport because you are going to be spending more of it there.

First, weekends. The other day, United Airlines quietly instituted a couple of quick changes that competitors are now looking at carefully. United said, for example, that it was adding a Saturday night stay requirement on all discounted fares where it competes with other major carriers - that is, on 65 percent of its market.

And of interest to those of us who make changes in itineraries booked on cheaper, nonrefundable tickets (that is, most business travelers), United is raising the change fee to $150 from $100.

United explained the changes in a statement that included this sentence: “In an environment where fuel prices are averaging almost $120 a barrel we are facing a cost increase.”

Yada, yada. Airlines, we feel your pain. But we are on the receiving end of the new cash-generating schemes, which, said Joe Brancatelli, the publisher of the subscription business travel site Joesentme.com, are “aimed directly at the business traveler.”

Air travel now becomes “a game of strategies and tactics,” he said, for the customers and the airlines.

Saturday night stay requirements are tiny poison pills that the major airlines once slipped into cheap advance-purchase fares to make them unattractive to business travelers, who hate having to stay on the road unnecessarily over a weekend.

The rule began disappearing in 2000 and 2001 when low-cost airlines, which do not have such restrictions, began taking more market share from the network carriers. But the Saturday night stay rule has been creeping back. And with its new policy, United has now moved the issue back into the main airfare pricing channel.

Credit cards? You may have noticed that airlines have been encouraging customers lately to pay for tickets using various means beyond credit cards. They are doing this partly to reduce their high credit card processing costs.

But do not use these other methods for airplane tickets. In the United States, under the federal Fair Credit Billing Act, a credit card company is required to return your money for a service not supplied, like an airplane trip. Debit payment agencies are not.

In recent weeks, some travelers on airlines like Oasis, Skybus, ATA, Aloha and others have had to scramble for refunds when those airlines abruptly stopped flying. In general, it is a bad idea to pay for an airline ticket with anything but a credit card, Brancatelli said, because resolving disputes is easier with a credit card company in your corner.

But worse, he said, “If your airline goes belly up and you paid with a debit card, you go to the back of the bankruptcy line with all the other unsecured creditors.”

Meanwhile, assuming you have planned ahead, grin and bear it.

“Airline lounges have gotten better, even though its amazing how much more crowded they are,” said Laura Davidson, a public relations executive from New York who travels frequently on business and now plans work to do if - and when - her flight is delayed.

“I have this three-section Tumi carry-on bag, and one section is just for use during delays,” she said. Among its contents are work folders and magazines like Vanity Fair - “which is a two-hour read that I never otherwise have time for,” she said.

“I try to time-manage instead of being frustrated,” she added.

“I prepare for the worst. Its all about diminished expectations. And sometimes youre surprised. I flew out to Chicago on a flight that arrived on time, and I was so happy that I thanked the pilot.”

WASHINGTON—Individuals took a shopping break in June, boosting their spending at the slowest pace in nine months as high gasoline prices and fallout from the housing slump made people think twice about buying.

The reported Tuesday that consumer spending edged up by just 0.1 percent. That marked a pullback from May’s brisk 0.6 percent rise and was the smallest increase since last September. Incomes, the fuel for future spending, rose by 0.4 percent in June for the second month in a row.

The spending and income figures aren’t adjusted for inflation. The consumer spending figure matched economists’ expectation, while income growth was just shy of analysts’ forecasts for a 0.5 percent increase.

Consumer spending plays a major role in shaping overall economic activity. In the first three months of this year, it was consumers’ brisk spending that prevented the economy from stalling. However, in the April-to-June quarter, consumers were much more subdued. They boosted spending at a pace of just 1.3 percent, the slowest since the final quarter of 2005, the government reported last week.

Even so, the national economy managed to stage a rebound, growing at a solid 3.4 percent pace in the second quarter, thanks to a revival in business investment, stronger sales of U.S. exports overseas and increased government spending. The housing slump continued to be a drag on the economy but not as much as it has been in previous quarters.

An inflation measured tied to the income and spending report showed “core” prices Д excluding food and energy Д moderated slightly. These prices rose 1.9 percent over the 12 months ending in June. That was a small improvement from the 2 percent annual gain for May.

Against this backdrop, Federal Reserve Chairman and his central bank colleagues are expected to hold a key interest rate steady at 5.25 percent when they meet next week. This important rate has stayed at that level for more than a year. Before that, the Fed had pushed up rates for two years to fend off inflation.

In June, consumers cut back spending on big ticket goods such as cars and appliances. Such spending dropped by 1.6 percent, reversing an increase of the same size in May. Spending on nondurable goods, such as food and clothes, was flat in June, compared with a big, 1.4 percent rise in the prior month. Spending on services, however, rose by 0.5 percent in June, up form a 0.1 percent increase in May.

High gasoline prices have left people with less money to spend on other things. The housing slump and weaker home prices have made people feel less wealthy and thus less inclined to spend as lavishly as they had during the five-year housing boom.

With income growth outpacing spending, Americans’ personal savings rate Д savings as a percentage of after-tax income Д improved.

The savings rate rose to 0.6 percent in June, up from 0.4 percent in May. Even with the better showing on this measure, economists caution that the picture of savings isn’t quite complete. The savings rate doesn’t capture gains from such things as real estate or financial investments.

As part of annual revisions, which are based on more complete data, the savings rate turned out to be higher in 2004, 2005 and 2006 than the government previously thought.

The savings rate was revised up to 2.1 percent from 2 percent for 2004. It was boosted to a positive 0.5 percent from negative 0.4 percent for 2005. And, it was moved up to a positive 0.4 percent from a negative 1 percent last year.