U.S. Interior chief defends travel spending, blasts 'insults'

By Valerie VolcoviciWASHINGTON (Reuters) - U.S. Interior Secretary Ryan Zinke on Tuesday defended his use of private planes and challenged reports of lavish spending, saying he was tired of "innuendo" and "insults."Zinke, who spoke before a Senate committee, has been dogged by the release of details of his use of charter planes and helicopters for travel, as well as recent receipts showing the department spent more than $130,000 to install new doors at his office at a time of proposed budget cut