US President Joe Biden's administration said on Tuesday it would appeal a judge's ruling ending a mask mandate on aeroplanes if public health officials deem it necessary to stem the spread of Covid-19.

The Centers for Disease Control and Prevention (CDC), to whom the administration was deferring, said that it would continue to study whether the mandates were still needed. The mandates apply to planes, trains and other public transportation and, prior to Monday's ruling, had been due to expire on May 3...