Maybe because I pay more attention now that I am busy with my new map-based venture, GourmetOrigins.com, but I have been coming across many airline commercials in the tube that use cool ways to display route networks and use them as a marketing tool.
Here is the first one from Easyjet, found in the London tube, displaying the main ski resorts that can be reached from different Easyjet destinations. I found this to be an elegant way to show useful information and a good way to suggest winter travel ideas.
Here another one, by Spanair, at the Barcelona Metro. Here the focus and the message is different, although the visual concept is similar. Spanair wants to highlight the scope of its network (including some destinations that are actually served by its Star Alliance partners, like Singapore), at a time when it is trying to position itself as Barcelona's main network airline, after it recent takeover by Catalan institutions.