DRIFTING: Stocks flipped between slight gains and losses Thursday as renewed worries about Europe's economy overshadowed an encouraging U.S. jobs report. The stock market started off the year strong but has drifted sideways over the last week.

MERGER THURSDAY: American Airlines and U.S. Airways agreed to merge in an $11 billion deal, creating the world's largest airline. Warren Buffett and 3G Capital, a private-equity firm, plan to buy the ketchup maker H.J. Heinz for $23 billion.

FINAL SCORE: The Dow Jones industrial average fell almost 10 points to 13,973. The broader S&P 500 index edged up one point to 1,521.