The blue prints for the freighters lack any engine of any form.
Fix add the engine component to the freighter.
Change
<RequiredComponentType>CargoModule</RequiredComponentType>
<ComponentType>LifeSupport</ComponentType>
to
<RequiredComponentType>CargoModule</RequiredComponentType>
<ComponentType>InterstellarDrive</ComponentType>
<FillerComponentType>LifeSupport</FillerComponentType>