Boeing Co shares dropped as much as 3 percent on Wednesday despite strong earnings, reflecting concerns about the aerospace company's cash flow, orders and costs.

Boeing Chief Executive Officer Jim McNerney said the company was on track to hit financial and production targets for the year, including delivering 750-755 jetliners, reaping more than $9 billion in operating cash flow and reducing production costs on its high-tech 787 Dreamliner.

"We delivered another strong quarter of operating performance," McNerney told analysts on a conference call. "Our long-term outlook also remains positive."

But investors appeared skeptical after the Chicago-based company said free cash flow swung to a negative $486 million in the quarter from a positive $615 million a year ago. Boeing cited spending on factories and tooling for new aircraft models.

Boeing stock was the biggest decliner in the Dow Jones industrial average, falling $2.73 to $150.60 in afternoon trading on the New York Stock Exchange. It fell as low as $148.85.

While analysts said the cash outflow spurred investors to sell, Boeing reaffirmed its cash outlook for the full year, and said it spent $2.5 billion on share buybacks in the quarter. Analysts noted that cash results are typically stronger at the end of the year.

Boeing also said production costs for its 787 Dreamliner rose by $793 million, pushing the total deferred cost balance on the program to $26.9 billion. Boeing had said costs would top out at about $25 billion, but last year lifted that to $26 billion.

The latest increase stemmed in part from delays in getting seats from supplier Zodiac Aerospace SA of France. The problem, which caused work to be done out of sequence and required extra Boeing workers, easily contributed several hundred million dollars to 787 production costs in the quarter, said Carter Copeland, an analyst at Barclays in New York. The total was not as bad as the $1 billion in new costs he expected.

McNerney said Zodiac had a fix for the problems, though "we don't anticipate a lot of it being worked through until the end of the second quarter."

But he said the delays will not disrupt production. Boeing hit its target of delivering 30 Dreamliners in the first quarter.

Boeing logged the slowest start to the year for jetliner sales since 2010, raising concerns that the order cycle for commercial aircraft may be turning after years of heady growth.

But McNerney said he expected orders for the full year to at least meet the total for deliveries, suggesting Boeing would log more than 600 additional sales.

McNerney said Boeing's 777 had already gotten 25 firm orders and commitments in the quarter, 18 more than the seven firm orders already on the books. He said he was confident those orders would be realized.

Barclays' Copeland said the order flow was less important than Boeing's overall backlog, which stood at more than 5,700 planes, or eight years of production, at the end of the quarter.

"This is all about delivering the planes that have been ordered not breaking ever higher records for orders," he said.

Boeing's net income rose to $1.34 billion, or $1.87 per share, from $965 million, or $1.28 per share, a year earlier.

Revenue jumped 8 percent to $22.15 billion as the company delivered 184 commercial aircraft, a 14 percent increase from a year ago. That helped drive revenue for the commercial airplane business up 21 percent to $15.4 billion.

Adjusting for a pension-related expense a year ago, profit per share rose 19 percent.