Air Mail Letter的用法和樣例：
例句
- It costs two dollars to send an airmail letter to the United States of America.
寄到美國的航空信件郵資是兩塊錢。 - An air-mail letter in the form of a lightweight sheet of stationery that folds into its own envelope for mailing at a relatively low postage rate.
航空郵件寫於輕薄紙張之上，裝入專用信封之中以較低郵費投遞的航空信件。
