Maybe you thought it was a rumor, but it's true. The third Friday of each December is National Ugly Sweater Day. And if you wear one on that day, you'll get special treatment by Alaska Airlines. Here's how it works.

If you're flying on Alaska Airlines or Horizon Air on December 15, wear your ugly Christmas sweater and you'll get early boarding. "Travel during the holidays can be stressful," explains Natalie Bowman, the company's managing director of marketing. "This promotion not only allows guests to board early, but gives people another opportunity to dust off that ugly holiday sweater hanging in the back of their closet." The airline will post pictures of the most ugly sweaters on its Facebook page.