US Airways Dividend Miles members who buy miles or give miles by Nov. 15, 2010 will get 100 percent bonus miles.

You don’t have to register for the bonus–the double miles offer will automatically apply when you purchase or gift miles. You can buy or gift up to 50,000 miles, which means you can get or give up to 100,000 miles with the bonus offer. Miles cost $.0275 per mile plus tax and your Dividend Miles account must be at least 12 days old to be eligible to buy miles.

Bottom line: While the 100 percent bonus on buying and gifting miles is described as a “limited time offer”, this is a recurring offer with US Airways. There is no guarantee that the program will offer it again, but if you pass on buying miles this time, there is a good chance that the 100 percent bonus will be offered again.