Airlines and other companies often have unencrypted, but hidden, wireless networks for maintenance workers. The free download NetStumbler detects all wireless networks in range, even if they’ve had their SSID hidden, so you can browse the Internet without paying fees.
NetStumbler (Windows only) displays the signal strength, name of the network (SSID), and encryption status. Most airlines and bus companies use some variation of their company name for their maintenance network. Before you go through the effort, check to see if there are free networks around, and don’t connect to computer-to-computer networks.
Use iStumbler for Macs.