Does the massive flier in the last goal in Wings of Liberty generate even more fliers?
The Leviathan does, actually, generate even more zerg leaflets, mutalisks specifically (or specifically? Regardless.).
Attempt and also see to it you have the artefact all set for when the Leviathan ultimately makes its look, and also bear in mind - it is "so high up in the air" that ground devices can not strike it in all. You'll require a load of vikings, wraiths, and also battlecruisers to bring that point down.
Sight - - If you had actually picked the "Destroy the Orbital Platform" goal rather, you would certainly have needed to deal with the beastie on that particular degree as an incentive purpose.