U.S. auto sales numbers for May were released this past week, and one trend was clear: Pickup trucks are hot. Ford (NYSE:F) saw sales of its F-Series line rise 31% over last May's totals. That led rivals' gains -- but nearly all of the pickup makers saw sales jump.

What's going on? In this video, Fool contributor John Rosevear looks at the economic forces driving these big jumps in full-sized pickup sales -- and at what they mean for profits at Ford and rival General Motors (NYSE:GM).