In a move to increase its focus on core operations, Boeing is selling three of its subsidiaries to Archer Aviation in exchange for a stake in the startup that focuses on electric vertical take-off and landing aircraft, known as eVTOLs for short.

Boeing's stake in Archer will amount to 19.75% of Class A shares of the company and comes with options to purchase more shares over the next four years, according a regulatory filing.

Shares of Archer surged 16% in premarket trading, while Boeing slipped 0.2%.

The subsidiaries include Wisk Aero, which has been developing an autonomous eVTOL, and SkyGrid, which is developing air traffic management systems for air taxis as urban air mobility moves from test flights to commercial operations. The third Boeing subsidiary being sold, Insitu, develops and manufactures high-altitude drones that have been used worldwide, including by the U.S. Navy.

Brian Yutko, Boeing vice president of commercial airplanes product development, said the deal "allows Wisk, SkyGrid and Insitu to accelerate capability development and time to market while ensuring Boeing capitalizes on its investments in these technologies over the past two decades through continued development in our core businesses."

For Archer, the transaction strengthens its position developing eVTOLs and the networks to support them. Insitu also helps Archer extend its military portfolio.

In announcing the acquisitions, Archer CEO Adam Goldstein said, "This is the next big step forward in becoming a diversified platform, rapidly growing our revenue base and bringing scale to our business."