Part 107 UAS pilot reported an airborne conflict with crewed aircraft during a mission. The UAS pilot took evasive action and descended the UAS.

Narrative

The airport is in uncontrolled airspace. There was a ton of snow in the area so I thought the airport was closed. Flew a couple of hours without issue. As my last mission for the day was wrapping up 90% completion; 2 planes took off from ZZZ. I noticed they were launching right into my flight path so I paused the automated mission; dropped altitude; let them pass; and continued mission after. I am unsure about the distance between aircraft as it happened quickly and I was focused on maneuvering out of their path. Note added to internal documentation as a preventive measure moving forward that includes airport's contact information.