Plans for a $100 million aerial gondola between the Seaport District and South Station appear to be hanging by a thread as the would-be private backer of such a tram negotiates with a property owner in its path.

Developer Millennium Partners, the same folks behind the recently green-lighted Winthrop Square tower, have not been able to reach a deal with Stavis Seafoods to co-anchor an industrial site on the waterfront in exchange for a property the company owns in the footprint of a potential tech campus a few blocks away.

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That impasse—as the Globe’s Jon Chesto notes—is having “a ripple effect.” The 12-acre tech campus is supposed to host a stop on the gondola. If Millennium and Stavis can’t reach an agreement, then the developer will have to reduce its build-out footprint—and then reduce the money available for transportation.

And that would mean no one-mile gondola 30 to 50 feet above Summer Street.

Which would not be that bad a turn of events for some. Chesto reports that City Hall is now lukewarm to the idea and that Millennium has offered other transit ideas instead. The aerial system once seemed, if not likely, then at least plausible. Stay tuned.