These days, it’s easier to name the companies that don’t have a travel app than the ones that do. But press us, and we can’t really think of any.

Industry players large (United Airlines, Starwood Hotels and Resorts, England) and small (beach locator, taxi finder, Slovakian ski resorts) are flooding our smartphones and tablets with vacation-related apps. The fingernail-size accessory touches on every component of travel: planning, booking, exploring, idling, photographing, filming, socializing and sharing. An app can map a route, track a flight, convert foreign currencies, edit holiday videos and even tell a German bartender, “Bitte, noch ein Bier.”

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Farewell, PC. Hope you enjoy your new life on the basement Ping-Pong table.

“Mobile is a transformational platform,” said Norm Rose, senior technology analyst at PhoCusWright, a travel market research firm. “It’s an essential tool for the traveler.”

(Andrew Bannecker for The Washington Post)

Over the past two years, the number of travel apps has surged along with mobile’s popularity. Last year, an estimated 17,000 travel apps crammed the virtual shelves; The Washington Post’s Travel section receives at least a dozen pitches for new products a week, many uber-specific. Sample: “Crystal Cruises has created an iPhone app to help travelers literally and figuratively share custom postcard images of their journeys via social media, e-mail and even snail mail.”

“There definitely is an overwhelming number of apps out there,” said Amanda Harary Cohen, a New York University senior majoring in hotel and tourism management, “but I appreciate that. When large or even start-up companies don’t have apps, it’s hard to take them as seriously. Everyone is going mobile.”

Among the everyones are higher-income households. In a 2012 study by the Luxury Institute, which looks at the consumer habits of the well-off, travel was the third most popular category of apps, with almost as many downloads as weather and news.

“Mobile travel is extremely important,” said Luxury Institute chief executive Milton Pedraza, “because travel is an experience, not just a widget.”

With plenty of free and inexpensive options, however, budget and mid-range travelers are becoming app-oholics, too. A PhoCusWright study from January, for example, found that more than a quarter of nearly 1,950 travelers had purchased a travel product on a mobile Web site or app. Of all app bookings, hotels ranked first, followed by such ancillary items as rental cars and airport transfers.

The trend switches, however, when air is involved. Most folks rely on flight-related apps for “disruption management,” such as checking arrival times and monitoring delays. Rose said that most people research and reserve flights the old-fashioned way, on computers. Yet the consultant predicts that Americans will spend $8 billion on travel app bookings by 2013, a sharp rise from $2.6 billion in 2011. Air might not be a holdout for long.

“Apps are in the early stage,” Pedraza said. “There are a lot of irrelevant apps. But as the quality gets better, we’ll see many more people using them. The day will come.”

Despite the glut, some of the more utilitarian apps have broken through the crowded marketplace, creating a more efficient and better informed traveler. Among the tools in heavy rotation: navigation, weather and itinerary organizers such as TripIt.

“Get the basic utilities — aggregate apps, currency changers, time zones,” said Keith Bellows, editor of National Geographic Traveler. “The granular of travel — trail maps, best surfing spots — is up to your own predilection.”

Niche apps, such as local public transportation schedules and museum tours, peak in relevance; once the trip is over, they’re as worthless as a subway token. When Robert Reid, U.S. travel editor of Lonely Planet, recently perused his iPhone, he stumbled over a couple of “strays,” including a Vancouver street food app from an October trip and a Pittsburgh walking tour from two years ago. Lately, Reid has been experimenting with video filming, editing and sharing apps. He also sees the wisdom of Google translator: “It has dozens of languages. You can say ‘I like cookies’ in Italian and speak Portuguese in Germany. Why wouldn’t everyone have that?”

Not all travelers, however, are hitching their stars to this rocket. Rolf Potts, a seasoned world traveler who founded the Web site and literary series Vagabonding, has been a slow and apprehensive adaptor. He purchased a smartphone last fall and recently tried AroundMe during a trip to Washington. And, yes, he liked it.

“If you’re standing on the corner, you can find a dozen places to eat,” he said of the feature. “It’s remarkably handy.”

Potts also consolidates his reading material, and lightens his backpack load, by storing newspaper and magazine articles on Instapaper. To get around Philadelphia, his current residence, he relies on the subway and bus apps. “It saves you the trouble of carrying a paper map,” he said. But he’s not abandoning his old dog tricks of travel.

“Apps have made travel more efficient,” he said, “but I’m a big believer that chance and human connection make a trip memorable.”

While some travelers hold on to tradition, others are leaping ahead to what’s next. Rose expects the fragmented world of apps to merge, allowing users to multitask with one press of the finger. He also predicts the emergence of voice-activated apps, in which the user asks a Siri surrogate to, say, arrange a 10-day trip to Thailand , including beach time in Phuket, an elephant ride in Chiang Mai and reservations at the best pad Thai restaurant in Bangkok.

We could call her Travel Agent 2.0.

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