http://consumerist.com/2008/08/15/as-of-august-5th-alaska/

As of August 5th, Alaska Airlines no longer accepts cash on its flights. In their words, welcome to “the convenience of a cashless cabin. Passengers will no longer need to hunt for cash to pay for on board purchases.” Finally! All that cash flitting around the cabin hurting people is a thing of the past. [Personal Finance Weblog]