US Air to Cut Executive Payroll 20 Pct  WASHINGTON (Reuters) - 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; plans to cut  its executive payroll by 20 percent, reducing pay and benefits  for its 3,000 managers and eliminating positions, The  Washington Post reported on Wednesday.