Reuters has reported "American, United Settle World Trade Center Developer's 9/11 Claims.  Silverstein has received several billion dollars from insurers to rebuild. He wanted to hold American and United responsible for their alleged negligence in failing to prevent the Twin Towers’ destruction by their hijacked planes. ... The settlement came a little over two years after a federal appeals court said Hellerstein had underestimated Silverstein’s losses on his 99-year lease for the site, signed six weeks before the attacks, clearing the way for the developer to seek more money from the airlines."  Read more here and here.