Boeing's second-quarter loss narrowed and revenue improved as the aircraft manufacturer delivered more commercial planes in the period.

Boeing Co. lost $611 million, or 92 cents per share, for the three months ended June 30. A year earlier it lost $1.44 billion, or $2.33 per share.

Adjusting for one-time gains, Boeing lost $1.24 per share. This was better than the loss of $1.54 per share that analysts surveyed by Zacks Investment Research expected.

Shares rose slightly before the market open on Tuesday.

Revenue climbed to $22.75 billion from $16.87 billion, mostly due to 150 commercial deliveries compared with 92 deliveries in the prior-year period.

The performance topped Wall Street's estimate of $21.86 billion.

"Our fundamental changes to strengthen safety and quality are producing improved results as we stabilize our operations and deliver higher quality airplanes, products and services to our customers," CEO Kelly Ortberg said in a statement. "As we look to the second half of the year, we remain focused on restoring trust and making continued progress in our recovery while operating in a dynamic global environment."

Boeing has been dealing with a variety of issues over the past few years.

On Sunday Boeing said that it expects more than 3,200 union workers at three St. Louis-area plants that produce U.S. fighter jets to strike after they rejected a proposed contract that included a 20% wage increase over four years.

The International Machinists and Aerospace Workers union said the vote by District 837 members was overwhelmingly against the proposed contract. The existing contract was to expire at 11:59 p.m. Central time Sunday, but the union said that a "cooling off" period would keep a strike from beginning for another week, until Aug. 4.

Last fall, Boeing offered a general wage increase of 38% over four years to end a 53-day strike by 33,000 aircraft workers producing passenger aircraft.

In June the National Transportation Safety Board said that its 17-month long investigation found that lapses in Boeing's manufacturing and safety oversight, combined with ineffective inspections and audits by the Federal Aviation Administration, led to a door plug panel flying off Alaska Airlines flight 1282, which was a Boeing 737 Max 9 aircraft, last year.

Boeing said in a statement at the time that it will review the NTSB report and will continue working on strengthening safety and quality across its operations.

The Max version of Boeing's bestselling 737 airplane has been the source of persistent troubles for the company since two of the jets crashed, one in Indonesia in 2018 and another in Ethiopia in 2019, killing a combined 346 people.

In May the Justice Department reached a deal allowing Boeing to avoid criminal prosecution for allegedly misleading U.S. regulators about the Max before the two crashes.

Boeing was also in the news last month when a 787 flown by Air India crashed shortly after takeoff and killed at least 270 people. Investigators have not determined what caused that crash, but so far they have not found any flaws with the model, which has a strong safety record.