Pretty soon, you'll be able to surf the Internet while flying. But this small new service may have unexpected consequences, changing the way airlines run their flights.

In-flight WiFi is definitely on the way: We've blogged about how JetBlue Airways is experimenting with limited WiFi on one flight already. And we've blogged how American Airlines will be rolling out high-speed broadband service this year on some of its Boeing 767-200 aircraft transatlantic flights. Elsewhere, the blog Jaunted is spreading the rumor that Southwest Airlines will also add in-flight WiFi soon.

But it seems highly likely that the airlines will have to do more than just offer WiFi. They will also have to filter the kind of websites passengers can access. For example, they probably won't want passengers to use the Internet to make Web-based phone calls. They will also probably feel obliged to screen out porn sites and other objectionable material, given that Congress recently has been pressuring airlines to shield child passengers from graphic content in their in-flight movies. In Australia, for instance, "Qantas Airways is designing its high-speed Internet services to block sites on "an objectionable list," including porn and violence," according to the Associated Press.

What's more, airlines are probably going to try to make a happy buck off of the Wi-Fi service by offering two-tiers of service, similar to a cable TV model with free basic cable and expensive packages for more comprehensive service. For example, JetBlue and American are considering using systems in which they offer passengers a free Yahoo-like portal on their seatback TVs, offering merely a handful selected of websites for passengers. The airlines may charge passengers fees of about $10 a flight for access to a wider array of websites.

These two factors (the need for airlines to filter Web content and the need to charge for different levels of Web access to maximize profits) may lead airlines to become online publishers, in a way.

In other words, when you use in-flight WiFi, you'll have to go to the airline's "home page", which will appear on your seatback TV screen. That home page offers an opportunity for creative publishing. Once the airlines start getting into the Internet publishing business, there may be surprising side-effects: "Matchmaking services" for people seeking cab rides when they land? Facebook for an airline's frequent fliers? eBay auctions for buying and selling frequent flier points? TripAdvisor-type destination guides exclusively written by and for members of an airline's frequent flier program? Match.com personal ads for travelers on particular routes, such as to Las Vegas?
Here are some of these ideas, sketched out...

—Why not make it easy for passengers to connect virtually to set up shared cab rides once they land, saving passengers from having to stand in long lines and spend big bucks? Airlines could use their Web portals on the seatback TVs to make it easy for passengers to say where they need to take a cab, and to meet up. The model here might be Virgin America's system for sending instant messages to other passengers in mid-flight. Or it might be such as Orbitz's service for travelers to share alerts with each other via text message and Web-enabled cell phones while on the ground.

—Why not turn frequent-flier miles into an eBay-style open market? That's what blogger and MacArthur Genius Grant-winner Jeff Jarvis proposes:

"In miles, the airlines have created a virtual currency with far greater reach and value than those on Second Life or Facebook....So let us bid on frequent flier seats with our miles. Let us trade and barter our miles with each other—I'll sell you this iPod for miles I want to use to get my vacation."

—Facebook for fliers? What if an airline like JetBlue created a social networking site for popular routes, or exclusively for members of its frequent flier rewards program? Jarvis, who blogs at BuzzMachine, suggests the following uses for such a service:

* We can ask our fellow passengers who live in or frequently visit a destination for their recommendations for restaurants, things to do, ways to get around.
* We can play games.
* What if you chose to fly on one airline vs. another because you knew and liked the people better? What if the airline's brand became its passengers? What if the airline even found ways to encourage more interesting people to fly with them because they knew that would attract and retain passengers (they could offer discounts and benefits to people who are active and popular in the social network)?
*They have a currency to pay for the information: They could reward us with frequent-flier bonus miles. Because they know who we are, they could even start to anonymously aggregate other data around this: "American Express Platinum customers recommend..."
Read Jarvis's full post at BuzzMachine

—What about destination guides exclusively written by and for members of an airline's frequent flier program, similar to TripAdvisor? JetBlue has already tried a version of this on their website with Blue Guides for five cities: San Francisco, New York, Orlando, Pittsburgh, and Houston. These guides would be a lot more interesting if passengers, in mid-flight, could read them and offer updated info on destinations and services. Meanwhile, Southwest is experimenting with having travelers share travel tips at their BeMoreProductive.com website, as The Cranky Flier has pointed out.

—What about Match.com personal ads for travelers on particular routes, such as to Las Vegas? We've blogged before about new cellphone tools to help travelers date. But once the airlines start publishing Web portals, why can't they offer "at-your-own risk" matchmaking services?

Feel free to share your thoughts below...