Boeing's chief financial officer, Greg Smith, told a conference call with analysts and reporters that additional spending on building up parts inventory for the 787-9 aircraft had been among factors affecting cash flow in the third quarter.

But he said the company sees potential to "revisit and possibly increase" its authorization for share buybacks, which return cash to shareholders. Boeing spent $1 billion buying back its shares in the third quarter.

Chief Executive Officer Jim McNerney said another 10 percent of Boeing's suppliers had joined the company's cost-reduction program, known as Partnering for Success, and the effort was lifting operating profit margins.

McNerney earlier on the call had said that Boeing was still in the first 25 percent of the initiative, having made deals with more than a third of suppliers, holding discussions with another third, "and then there's another third that we're jousting with a little bit."

Questioned further, McNerney said he did not want to "leave the impression that we're not making progress. We are. It would be fair to say that over the last three to four months that another 10 percent of our partners have started working with us on a contract basis."

Earlier Wednesday, Boeing reported an 18 percent rise in profit in the third quarter, but said cash flow had declined, raising concern among analysts about rising costs of producing the 787 Dreamliner.

Boeing's shares were down 3.3 percent at $122.94 in early afternoon trading on Wednesday.

(Reporting by Alwyn Scott; Editing by Leslie Adler)