Over the weekend, hundreds of flights were canceled or delayed at Moscow’s Sheremetyevo and St. Petersburg’s Pulkovo airports. Other airports in western and central Russia also faced disruptions because of Ukrainian drone attacks.

Ukraine said it struck a Russian air base on Saturday, while Russia continued to attack Ukraine with hundreds of drones overnight as part of a stepped-up bombing campaign that has dashed hopes for a breakthrough in efforts to end the more than 3-year-old war.