9 Ways to Score an Upgrade on Your Honeymoon Flight 

In an article from Brides.com By Katie Hammel

Katie lists 9 inventive ways to Upgrade your Honeymoon Flight from Volunteering your seat to Bidding for an upgrade.  This is a good article to read at the start of your wedding planning process, because Advice #1, is to get a particular type of credit card with Frequent Flyer Miles and charge the Wedding Expenses to pay for your Flight Upgrade!  Another good reason to read this article at the Beginning of your planning, is the advice to "Pick the Right Flight".  Picking off-season flights, or weekends with fewer business travelers may work in your favor.

All in all, it may be highly unlikely to Upgrade your flight cheaply, but knowing there ARE ways certainly doesn't hurt.