According to officials familiar with the situation, the announcement that the US is ending its war in Syria and withdrawing all ground troops also applies to the air war. US warplanes will stop striking Syria after the troops have left. 

The Pentagon refused to confirm the decision officially, saying that they will keep conducting airstrikes so long as US troops are on the ground. After that, they said they "would not speculate."

US warplanes have been killing a large number of civilians in recent weeks, focusing on strikes against ISIS-held towns along the Iraqi border. Those strikes have been hitting populated areas. 

The Pentagon seems to be planning to continue these strikes for now, though to what end isn't entirely clear, as it would be backing Kurdish YPG attacks on towns in the lead-up to a Turkish invasion targeting the Kurds.