FORT WORTH, TX — Look — up in the sky! It’s a bird; it’s a plane. It’s … in-flight internet censorship!The two largest U.S.-based air carriers, American Airlines and Delta Airlines, will offer passengers in-flight WiFi service, but only of “approved-for-family-viewing” virtual destinations, the carriers announced recently. In addition, access to online telephone services like Skype will be blocked.

The rationale behind blocking Skype and its voice-over-internet-protocol brethren is easy to comprehend: The services could have a negative impact on the revenue airlines garner from in-flight phones embedded in seat backs. With revenues plummeting across the board, airlines need all the pennies they can snatch.

Restricting access to websites is a bit tougher to understand. Why prevent people from logging on to porn sites when, if travelers are determined to view adult content on their portable devices, they simply can insert a DVD or call up smut on their iPods?

Blame conservative family values organizations for the myopia. The Alliance Defense Fund, for example, mounted a major campaign to enlist flight attendants in its mission to ensure online porn didn’t warp adult minds mid-way across the Atlantic or cause child abuse between New York and Los Angeles.

Delta was the first to cave to the pressure, announcing in early October that it had changed its mind and would offer only filtered internet access. American followed suit a few days later. As other air carriers consider their flight paths, ADF Special Counsel Patrick Trueman said his group wants citizens to bombard them with the message that their income will take a nose dive if they don’t knuckle under, as well.

“We want flight attendants concerned about our safety and our comfort, not about regulating pornography on the Internet,” Trueman told Christian website OneNewsNow.com. “Make your calls to these companies because, as we’ve demonstrated with the Delta situation, phone calls to the company work.”

Although Delta was the first to announce it will filter internet access to combat the apparent epidemic of porn browsing in the air, American was faster to market with the service. American’s Gogo in-flight internet service, launched unfiltered in August as a six-month trial on flights from New York to San Francisco and Los Angeles to Miami (and vice-versa), is provided by Aircell. The carrier said it has received no reports of porn at 30,000 feet, but filtering is “an appropriate measure to take.”

American has reason to be gun-shy about sex-related issues. In March, a Texas woman filed suit against the company after a male passenger ensconced himself in the seat next to hers and proceeded to stare at her while he masturbated. Although online porn was in no way involved in the incident, American and conservative groups have used the lawsuit as one reason to install filters.

JetBlue, Continental and Qantas Airways also plan to provide filtered in-flight internet service.