To be effective, a space elevator would have to deliver the payload all the way out to geostationary orbit altitude. At that hight, the payload would already be

To be effective, a space elevator would have to deliver the payload all the way out to geostationary orbit altitude. At that hight, the payload would already be in orbit without adding any additional horizontal velocity. But almost all of the height is higher than you can float a lighter than air craft (42164km vs ~40km for lighter than air craft).