Setbacks and Air Rights

1920's or so skyscraper with all the setbacks represents the old zoning laws...believe the new place down Lexington Avenue, which is rising up sort of shoe-horned in, is probably built on basis of air rights purchased from low rise buildings on either side of it.

I ran a lengthy posting on air rights not so long ago...let me see if I can direct you to what date...

Yes, it was back on Tuesday, July 2 with the title

What are "Air Rights," anyway, and why are they so important in Manhattan? 

 I suggest you scroll back to that to get the FULL story on how all these air rights work in NYC.