When airlines (slowly) started introducing in-flight Internet access to their flights, they were very quick to point out that “VOIP calls” would not be possible. VOIP stands for “Voice over Internet Protocol”, and basically means making phone calls over the Internet. All popular VOIP applications like Skype and Vonage have been blocked.
The airlines, and the provider behind the service obviously do not want a plane full of people chatting on the phone, yelling loudly about how they just made a fortune on the stock market. The other reason is of course because each flight only has a limited amount of data to share between all the passengers. If half the plane suddenly starts calling their aunts and uncles, regular web browsing would become impossible when all the bandwidth is sucked up by phone chatter.
Of course, when you tell people they can’t do something, their natural response is to see how they can prove you wrong. It took a week, but the block on VOIP calls has been successfully bypassed. By using a web service called Phweet, passengers have been able to make phone calls to their friends. The system only works with people who have a Twitter account, but it’s better than nothing. Of course, now this workaround has been published, it will only be a matter of time before the fun comes to an end, and the creative minds will have to find another working solution.
(Source: Wired)