Stock index futures indicated a flat to higher open on Monday, with investors wary of taking risky bets into year-end.

Retail stocks could see support after U.S. retailers posted a better performance during the 2009 holiday shopping season, with sales up 3.6 percent, as tracked by MasterCard Advisors unit SpendingPulse.

Airline stocks may be in the spotlight as the United States tightened airline security amid growing questions about how a Nigerian man with alleged ties to militants smuggled explosives aboard a transatlantic flight and attempted to blow up the plane.

With the S&P 500 nearly 25 percent higher for the year, investors are keen to hold on to profits. U.S. stocks rallied in a shortened preholiday session Thursday, closing at 2009 highs. Markets were closed Friday for the Christmas holiday, and Monday's volume will likely be light as many traders take off the week between Christmas and New Year's.

S&P 500 futures rose 0.8 points and were above fair value, a formula that evaluates pricing by taking into account interest rates, dividends and time to expiration on the contract. Dow Jones industrial average futures added 4 points, and the Nasdaq 100 futures gained 4.25 points.

Kraft Foods Inc will be in focus as Italian chocolate major Ferrero is still examining its options on a possible bid for Britain's Cadbury PLC . The UK confectioner has rejected a $16.2 billion offer from Kraft. U.S.-based Hershey Co and the family-owned Ferrero have said they were contemplating bids.

European stocks rose for a fifth straight session on Monday, adding to gains before the Christmas break, as an overnight rally in Asian shares boosted sentiment, but volumes were thin with London markets closed.

Oil hit a four-week high above $78 a barrel as colder weather across the U.S. and fresh signs of an economic recovery helped boost the outlook for fuel demand.

(Reporting by Leah Schnurr; editing by Jeffrey Benkoe)