US Airways is running tiered bonuses for mileage purchases through August 31.

For purchases of 50,000 miles you get 50,000 bonus miles, and your 100,000 miles cost you 1.88 cents per mile.

The American Merger and Star Alliance Awards

US Airways has been dubbed the ‘consolidator of Star Alliance premium class seats’ (credit to eponymous coward) since seats that aren’t expected to be sold (distressed inventory) tend to be offered as awards, and US Airways has been the most aggressive about letting members straight up buy those seats cheaply via purchased miles — even putting awards on hold before buying the miles (which post instantly).

Here’s my guide to using US Airways miles to book awards.

It’s an open question whether the merged American-US Airways will similarly become oneworld’s official consolidator once US Airways joins oneworld, likely by the start of 2014.

US Airways miles will ultimately, of course, become American miles (and one imagines they’ll be transferrable to American before the frequent flyer programs are actually combined into one).

While buying US Airways miles can get you Star Alliance awards now — bookable through the end of airlines’ schedules — you’ll still be able to buy miles cheap on a regular basis for Star awards once US Airways leaves the alliance.

When Avianca sells miles with a 100% bonus the cost is 1.5 cents per mile, and they allow one-way awards without Starnet blocking though if you can’t book the flights you want online (and you can’t book awards in a mixed class of service at all) their call centers can be difficult to worth with. That offer is back for August, too, which I’ll post on shortly.

No Airfare Spending Bonuses for the Mileage Purchase

US Airways mileage purchases are processed by points.com which means they don’t show up as airfare, and thus don’t earn bonuses from credit cards like Chase Sapphire Preferred (double points) or American Express Premier Rewards Gold (triple points) that bonus airfare spend.

Should You Buy Miles With This Offer?

Buying miles at a 100% bonus from US Airways used to be an amazing deal. Three years ago their award chart was less expensive (e.g. 80,000 miles for business class to Europe). And prior to September 2010 miles normally cost 2.5 cents apiece. In October 2011 they raised the standard price of miles to 3.5 cents apiece.

Since US Airways runs mileage purchase bonuses nearly every month, though sometimes targeted and other times in varying amounts, they’ve more or less jacked up the price only to be able to discount it, making the discounts look better than they actually are.

Make no mistake, they can still be a good deal, but not good enough in my view to stock up miles speculatively. Instead, I’d use this deal to top off an account towards a specific award or to buy outright a ticket that you can immediately book (getting airfare at a discount).

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