airmail 與 regular mail（普通郵件）的區(qū)別在于運輸方式，airmail 通過航空運輸，通常速度更快，適用于國際或遠距離郵件。

airmails (noun) - letters or packages sent by air, typically faster than regular mail.

• The company uses airmails to ensure that documents reach their destination within 24 hours. (使用航空郵件確保文件在24小時內(nèi)到達目的地。)
  She sent the package by airmail to expedite its delivery. (她通過航空郵件寄送包裹以加快遞送速度。)

Airmails are a method of sending mail that involves transporting letters, packages, or other items by airplane. This method is typically faster than sending mail via land or sea, making it a preferred choice for urgent or international deliveries. The term "airmail" can also refer to the service or system that handles such mail. In some contexts, "airmail" can be used as a singular noun, but it is more commonly used in the plural form, "airmails," to refer to multiple items sent by air.