* Indexes on track for third straight week of gains
* Boeing may be able to boost Q4 deliveries of 787s
* Priceline profit beats expectations, but outlook weak
* Futures up: Dow 22 pts, S&P 1.1 pt, Nasdaq 4.5 pts
By Ryan Vlastelica
NEW YORK, May 10 (Reuters) - U.S. stock index futures pointed to a flat open on Friday, though indexes remained on track for a firm finish to the week, which repeatedly saw the indexes scaling new highs.
The length of the recent rally has surprised many, and the upward momentum may be difficult to sustain without further trading catalysts such as first-quarter earnings reports, which are nearing an end. The S&P 500 ended a five-day streak of record closing highs on Thursday, while the Dow broke a two-day streak by dipping modestly.
Still, investors expect shares to generally trend higher, given the Federal Reserve's accommodative monetary environment and encouraging data on the labor market, including jobless claims on Thursday and last week's payroll report.
"Between the jobs report, quantitative easing and a 0 percent interest rate policy, there's no question that there's a floor under the market and that it wants to go up, even if some sectors are overdone," said Chris Bertelsen, chief investment officer of Global Financial Private Capital in Sarasota, Florida.
Boeing Co will be in focus, a day after the company said it had succeeded in getting its factories to churn out 787 Dreamliners at a faster pace this week, a change that came sooner than expected and positions the plane maker to possibly deliver more of the high-tech jet than forecast.
S&P 500 futures rose 1.1 point 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 22 points and Nasdaq 100 futures rose 4.5 points.
For the week, the Dow is up 0.7 percent, the S&P is 0.8 percent higher and the Nasdaq has gained 0.9 percent. It is the third week of gains for all three indexes.
Energy shares may face pressure on Friday as crude oil dropped 2.1 percent on signs of rising supply.
The group, along with other cyclical sectors closely tied to the pace of economic growth, is among the biggest gainers in the recent rally, spurred by an improved global outlook.
"We're seeing a real rotation out of defensive names and into groups like technology and industrials," said Bertelsen, who helps oversee $2 billion in assets. "That's keeping the market moving and preventing it from plateauing."
Priceline.com Inc late Thursday reported first-quarter earnings that beat expectations, though its second-quarter outlook disappointed. Shares edged 0.5 percent lower to $733.60 in premarket trading.
Molycorp Inc reported a first-quarter loss that widened from the prior year, though revenue rose sharply, sending shares up 6.6 percent to $5.96 before the bell.
With 89 percent of the S&P 500 having reported, 66.7 percent have topped profit expectations, above the average since 1994 of 63 percent. However, only 46.4 percent of companies have beaten revenue expectations, well under the average since 2002 of 62 percent.
Activist investor Carl Icahn and Southeastern Asset Management proposed an alternative to a $24.4 billion buyout deal for Dell Inc that involved giving shareholders an option to receive either $12 a share in cash or $12 in additional shares valued at $1.65 each.
Shares of Dell rose 0.5 percent to $13.39 in premarket trading.
Among the most active premarket movers, Pain Therapeutics Inc plummeted 47 percent to $2.80 after it said that Pfizer Inc, its marketing partner for painkiller Remoxy, was yet to decide on continuing to seek regulatory approval for the drug.
On Thursday, an extended rally for U.S. stocks came to an end as equities dipped slightly in a volatile session and shares of Apple Inc declined.