If you are a frequent or sometime-flyer on one of the five largest U.S. airlines, you are likely a "have-not" when it comes to onboard Wi-Fi.

The exception to the rule are customers of Delta Air Lines, the largest U.S. carrier in terms of passengers as well as the leading operator of Wi-Fi-outfitted aircraft at 70% among five biggest U.S. airlines, according to a recent PCWorld report on the tech attributes of U.S. airports and airlines.

The ranking actually characterizes Delta as the techiest of the ten largest U.S. airlines when you also consider the availability of outlets and USB ports at its gates; its ubiquitous social media presence, the quality of its mobile apps, and mobile check-in options.

But, back to Wi-Fi: Delta's entire mainline domestic fleet offers Wi-Fi from its provider, Gogo ( Meanwhile, 39% of its regional fleet with two-class configuration is already wired up, too, says Paul Skrbec, a Delta spokesman.

This means you need to consider the Wi-Fi gap when it comes to next largest major U.S. carriers. According to PC World's accounting, the Wi-Fi availability at American Airlines is 30%, Southwest is 19%, US Airways is 17%, and United-Continental 2%.

So, if Alec Baldwin makes good on his pledge to never fly American Airlines again after his Words with Friends flare-up and Saturday Night Live defense, then he might consider Delta as a replacement for connectivity's sake.

Next Steps: International Coverage

But, if Delta passengers hope to browse the Internet and email from on-high on international flights, they are going to have to wait awhile.

"We are actively evaluating our solutions for our international aircraft, but I don't have projections on when we would announce what the solution will be," Skrbec says.

Mark Sullivan, author of the PCWorld piece, writes that "we also noted a trend toward satellite-based (as opposed to ground-based) Wi-Fi that will work internationally, not just on domestic flights."

United-Continental is one of the carriers which plans to get in on the satellite action.

"In 2012, we'll start outfitting satellite-based Wi-Fi on the entire mainline fleet," says United-Continental spokesperson Rahsaan Johnson. "When completed, customers will be able to use Wi-Fi worldwide on United Airlines aircraft, including former Continental aircraft."

The Little(r) Guys

Some of the smaller U.S. airlines are doing a solid job on the Wi-Fi front.

For example, Virgin America, which isn't among the 10 largest U.S. airlines, has Wi-Fi on all its aircraft and will be the launch customer early next year for Gogo's "even faster" ATG4 service, says airline spokeswoman Abby Lunardini.

And, you don't have to be on the prowl for AC plugs on Virgin America because its aircraft features "power outlets at every seat across all cabins," Lunardini says.

Like Virgin America, AirTran, which is merging with Southwest, has Wi-Fi on all its aircraft.

And, among the other ten largest U.S. airlines, Frontier has 35% of its aircraft Wi-Fi-equipped, while JetBlue, which has been out-front with its in-flight entertainment system, strikes out in Wi-Fi features with none of its planes Wi-Fi-enabled, according to PCWorld's statistics. Of course, you can watch live TV, but that's material for another story.