A stable or unstable covid patient may be referred airway (plane or helicopter). Is there a risk from aerosols and pressure? / 下午好 covid19稳定或不稳定的患者可以通 过空运（飞机或直升机）转诊 吗？有没有气溶胶传播危险？ 气压的变化是否会对患者带来 隐患？