Newark Yankees would have been interesting. I bet this is deeper than just Newark, I bet if we search our brains the Yankees may have done something to annoy the Mets at some point.
The Mets declined, saying their organization would only do something like that with mutual and immediate reciprocity as they did with the Yanks when they put a minor league team in Brooklyn and allowed the Yanks to do the same on Staten Island.
But those were permanent moves. This was only for a year, the Yankees argued.
The Mets declined.
via Izenberg: Mets blocked Yankees from bringing minor league team to Newark for a season | NJ.com.