Air mail 封筒
You're referring to the classic airmail envelopes! 📨
Airmail envelopes, also known as air mail envelopes or aerogrammes, are special envelopes designed for sending mail by air. They are typically made of lightweight, thin paper or plastic and have a special adhesive strip or flap that allows them to be sealed easily.
Here are some interesting facts about airmail envelopes:
- First introduced in 1918: Airmail envelopes were first introduced by the United States Postal Service (USPS) in 1918, during World War I, to speed up mail delivery between the US and Europe.
- Special design: Airmail envelopes have a distinctive design, with a red or blue stripe running along the top or side of the envelope. This stripe indicates that the mail is being sent by air.
- Lightweight: Airmail envelopes are designed to be lightweight, which helps reduce fuel consumption and costs during air transportation.
- Special adhesive: The adhesive used on airmail envelopes is designed to be strong enough to keep the envelope closed during flight, but weak enough to be easily opened by the recipient.
- Limited use: Airmail envelopes are typically used for sending mail between countries or for sending mail that requires expedited delivery. They are not commonly used for domestic mail.
- Collectible: Airmail envelopes have become collectible items, especially those with rare or unique designs, stamps, or cancellations.
Overall, airmail envelopes are an important part of postal history, and their design and functionality have played a significant role in shaping the way we send mail today. 📨