Despite having worked on aircraft software for most of my career, my knowledge of aeronautics is weak. I have often wondered why no one has tried to design and

Despite having worked on aircraft software for most of my career, my knowledge of aeronautics is weak. I have often wondered why no one has tried to design and build an airship with an envelope in the shape of a lifting body. The structure might have additional weight to hold the desired shape, and it would have to take off like an aircraft, but wouldn't the added lift provide significant advantages? I know I must be missing something fundamental. Can someone more knowledgeable tell me what it is?