WASHINGTON—A U.S. appeals court on Thursday rejected a request from Tesla Inc. to quickly reinstate higher civil penalties for automakers who fail to meet U.S. fuel economy standards. The Second Circuit U.S. Court of Appeals had rejected the electric vehicle maker’s request in April for immediate action pending a National Highway Traffic Safety Administration (NHSTA) review. Tesla again asked the court in August to take immediate action. The court on Thursday issued a brief order rejecting that request. Tesla sells credits to other automakers to help them meet government vehicle emissions requirements, and says those credits are less valuable due to changes in rules made by former President Donald Trump’s administration. In August, NHTSA issued a notice saying it could impose higher penalties for prior model years. It submitted a draft proposal to the White House in December for regulatory review. Automakers have said hiking penalties could cost them at …