USAir Details Plan to Be Low-Cost Carrier  WASHINGTON (Reuters) - Bankrupt US Airways &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=UAIRQ.OB target=/stocks/quickinfo/fullquote"&gt;UAIRQ.OB&lt;/A&gt;  detailed plans on Monday for becoming a low-cost carrier,  saying it will overhaul its flight schedule and sharply boost  aircraft turnaround times beginning in February.