US Airways is extending its 100% bonus on purchased miles until December 7. Miles can be had for 1.88 cents. Bill wrote about this promo more fully last month.

This deal seems to run every other month, so I don’t see a reason to stock up. And in general, I don’t like the price of $1,938 + taxes to fly in roundtrip business class to Europe or slightly less to Asia.

But some sweet spots on US Airways’ chart are incredible. Consider the award I bought yesterday.

It has 40 hours in business class–30 of which I’ll fly ;). If you bought the 100k miles for the promo for $1,888 and payed the $309 in taxes and fees, that would be $2,197 for 40 hours of flying in flat beds. That would be a decent price for economy, and you’d get it in business class.

The point is that for spectacular awards, buying miles for 1.88 cents makes sense. I got 2.64 cents of value from each mile after all.

And of course, this promo is fantastic to top up your account that is a few miles short of a dream award.

For more sweet spots, see

US Airways Award Chart Sweet Spot: Australia via Asia,

Anatomy of an Award: Exploiting a South Asian Sweet Spot on the US Airways Award Chart,

and

US Airways Chart Sweet Spots: South America.