Marketers searching for the world's best captive audience may need to look up -- 30,000 feet up, that is. According to a report in The New York Times, JetBlue Airways will be the first carrier to offer free email and IM service as early as Tuesday on one plane, while American Airlines, Virgin America and Alaska Airlines are working on offering web access for a small fee within the next few months.

"I think 2008 is the year when we will finally start to see in-flight internet access become available," Henry Harteveldt, an analyst with Forrester Research, told the paper. "But I suspect the rollout domestically will take place in a very measured way. In a few years time, if you get on a flight that doesn't have internet access, it will be like walking into a hotel room that doesn't have TV."

In a TechCrunch post, blogger Erick Schonfeld hypothesized that the airlines might consider using in-flight Wi-Fi to sell ads. For now, the airlines are expected to charge about $10 for internet access.