US Air Unions Object to Plan for Cuts  WASHINGTON (Reuters) - Big labor unions at bankrupt US  Airways Group Inc. &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=UAIRQ.OB target=/stocks/quickinfo/fullquote"&gt;UAIRQ.OB&lt;/A&gt; claimed on Tuesday the carrier  has fallen far short of proving that it must have immediate  court-imposed wage and other cuts to survive.