US STOCKS-Futures imply flat open; energy on track for big drop
* Oil falls 6 percent, Exxon tumbles in pre-market
* Airline shares rally on drop in crude prices
* Indexes could notch sixth straight weekly advance
* Dow up 20 pts, S&P down 1 pt, Nasdaq up 12.75 pts (Updates prices)
By Ryan Vlastelica
NEW YORK, Nov 28 (Reuters) - U.S. stock index futures pointed to a flat open on Friday, as the market's recent upward bias looked to continue in a holiday-shortened session, though energy shares saw heavy pressure as crude oil tumbled to a four-year low.
Wall Street was closed for the U.S. Thanksgiving holiday on Thursday and will shut three hours earlier on Friday. Trading volatility could spike since many market participants were extending the holiday.
U.S. crude futures slumped 6 percent to $69.26 per barrel. It was the biggest one-day drop for crude since September 2011, and the decline brought prices to their lowest since 2010. On Thursday, OPEC decided not to cut output, which could leave oil markets heavily oversupplied.
Energy shares have been under pressure throughout 2014 as crude prices have slid more than 30 percent from a recent closing high. The S&P energy sector is the only S&P 500 industry group to be lower for the year, down 4.3 percent. Continuación...