(Adds detail from conference call, updates share price)
NEW YORK, July 26 (Reuters) - Boeing Co shares soared almost 8 percent to a record high on Wednesday after the world's biggest plane maker posted second-quarter profit and cash flow well ahead of Wall Street estimates and lifted its full-year forecasts, helped by aggressive cost cutting.
Boeing has reduced spending by streamlining production, cutting jobs and winding down development costs, which has dramatically improved profit and cash flow.
Its 787 Dreamliner contributed about $530 million in cash in the quarter, the second-largest amount in the six years since Boeing started delivering the carbon fiber planes.
Boeing shares rose 7.9 percent to $229.20 in midday trading. The stock has soared 37 percent this year.
The company's cash from operations, at nearly $5 billion in the quarter, was roughly double estimates of about $2.5 billion.
"Monster cash flow," said analyst Robert Stallard at Vertical Research. The results were "about as close to perfect as it gets from Boeing," he added.
Military aircraft sales fell 4 percent to $6.8 billion, but profit jumped 50 percent and margins widened 4.6 percentage points, another sign of cost-cutting.
Boeing now needs to keep speeding up production of 737s and stay on schedule with 787-9 and 787-10 production and the transition to the 777X, a replacement for its 777 jetliner, said Ken Herbert, an analyst at Canaccord Genuity.
The extra cash allowed Boeing to add $1.5 billion to its 2017 operating cash flow forecast, now about $12.25 billion. Boeing will increase share buybacks this year by $3.5 billion, to about $10 billion. And it will make $3.5 billion in additional pension contributions this year to reduce future costs.
Boeing said it will cut full-year capital expenditure by $300 million, but that was expected since the company has made most of the big investments in its 777X wing factory and the 737 MAX and 787-10 programs, said analyst Richard Aboulafia at Teal Group.
Boeing Chief Executive Dennis Muilenburg said that the capital spending reduction reflected declining 777X costs and was a sign that the program remains on track for the first aircraft to reach airlines in 2020.
The company lifted its full-year forecast for core earnings, which exclude some pension costs, by 60 cents to between $9.80 and $10.00 per share.
Boeing swung to a profit of $1.76 billion, or $2.89 per share, in the second quarter, from a loss of $234 million, or 37 cents per share, a year earlier that reflected charges related to the 787, 747 and KC-46 tanker aircraft programs.
Core earnings, which excluded some pension and other costs, were $2.55 per share in the quarter.
Revenue fell 8.1 percent to $22.74 billion.
Analysts expected core earnings of $2.30 per share on revenue of $23 billion, according to Thomson Reuters I/B/E/S. (Reporting by Alwyn Scott in New York and Ankit Ajmera in Bengaluru; Editing by Saumyadeb Chakrabarty, Jeffrey Benkoe and Bill Rigby)