Chicago ? Boeing Co. swung to a $623 million profit in the first quarter and raised estimates Wednesday for revenue and earnings into 2005, citing signs of stabilization in the long-shaky commercial jet market and impressive sales from its military business.

CEO Harry Stonecipher said he was encouraged by the improving airplane market but acknowledged continuing difficulties with Boeing’s efforts to end controversies over its ethical practices, which have left both a lucrative air-tanker deal and its ability to bid on government rocket contracts on hold for months.

Boeing CEO Harry Stonecipher talks about the Boeing 7E7 Dreamliner airplane during a Dec. 16 news conference in Seattle. Boeing Co. reported on Wednesday a 23 million profit in the first quarter.

“It’s certainly frustrating,” he said. “We’re trying to get everything out in front, be very open about what’s going on and deal with every problem as it raises its ugly head.”

Ethical problems aside, Boeing’s large backlog of key military contracts helped revenue at its defense and space unit surge 18 percent from a year earlier, enabling it to post far better earnings than had been expected.

Net income amounted to 77 cents a share, compared with a net loss of $478 million, or 60 cents a share, a year earlier.

The company’s per-share earnings, which got a 12-cent boost from interest from a federal tax refund, easily outpaced analysts’ estimate of 44 cents per share. The estimate was compiled by Thomson First Call before Boeing indicated last week that it would exceed it by a significant amount.