airline vs. airlines：
airline：通常指單一的航空公司。
airlines：通常指多個航空公司或航空公司行業(yè)整體。

n.

a hose that carries air under pressure

同義詞：air hose

a commercial enterprise that provides scheduled flights for passengers

同義詞：airline businessairway

單數(shù)形式：The airline offers flights to over 100 destinations worldwide.
中文：這家航空公司提供飛往全球超過100個目的地的航班。
復(fù)數(shù)形式：Many airlines have introduced new safety measures due to the pandemic.
中文：由于疫情，許多航空公司引入了新的安全措施。

Airlines are businesses that operate aircraft to transport passengers and cargo. These companies typically have a fleet of airplanes and a network of routes that connect various destinations. Airlines can be categorized into several types based on their services, including major airlines, regional airlines, low-cost carriers, and cargo airlines. They play a crucial role in global transportation, commerce, and tourism, providing a fast and efficient means of travel across long distances.