The fate of Energy Future Holdings Corp.’s transmissions business, Oncor, is once again up in the air, under a new bankruptcy exit plan for the Dallas electricity giant. Oncor, a business that carries electricity to some 10 million Texans, is back in play as a takeover target, under a bankruptcy emergence plan Energy Future filed Sunday, after a deal to buy it fell apart. Court papers outlining Energy Future’s new chapter 11 exit plan indicate there is room for NextEra Energy Inc. or other strategic investors to make an offer for Oncor. The new plan also has room for the deal that was stymied in regulatory action to work its way to completion, according to a statement from a spokeswoman for Hunt Consolidated Inc., the Texas company leading the deal. Hunt has asked state utility regulators to reconsider, and that effort continues, the statement said.