calm air meaning in English

平静航空公司
无风

Gossamer is floating in calm air .
空中飘浮着游丝。
The system worked fine in relatively calm air during the day
这套系统在天气相对平静的白天可以正常工作。
Because wake vortices can persist in calm air for several minutes ( extending for as far as eight miles ) , the federal aviation administration requires minimum distances between aircraft , based on size
机尾涡流可以在无风的空气中停留几分钟，向后延伸达12公里，所以美国联邦航空总署按照飞机大小而规定了飞机之间的最小安全距离。