Aerospace giant Boeing Co. reported a net loss of $663 million for the fourth quarter of 2020, as the company continues to feel the impacts of the COVID-19 pandemic.

The company posted a quarterly loss of $2.33 per share on revenue of $17.91 billion. Analysts had expected earnings of $1.51 per share on revenue of $18.14 billion.

Boeing’s results were weighed down by labor and supply chain strains, as well as a drop in commercial airplane deliveries. The company delivered just 24 planes in the fourth quarter, down from 63 in the same period a year ago.

The company’s revenue was boosted by an increase in defense and space services, while its cash balance also rose to $25.7 billion at the end of the quarter from $22.1 billion at the end of the third quarter.

Boeing reaffirmed its 2023 sales guidance and said it expects the commercial airplane market to recover in the second half of 2021. Despite the losses, Boeing CEO Dave Calhoun expressed optimism about the company’s future.

“We remain focused on the health of our business, our people and our customers as we continue to navigate a challenging environment,” Calhoun said.

The company’s stock price dropped more than 4% in after-hours trading following the announcement of its earnings.