Delta Stock Up After Pilots' Deal Reached  NEW YORK (Reuters) - Delta Air Lines Inc. &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=DAL.N target=/stocks/quickinfo/fullquote"&gt;DAL.N&lt;/A&gt; has  reached a tentative contract with its pilots that will save the  cash-strapped airline \$1 billion annually, sending its shares  soaring almost 25 percent on Thursday.