Are normal enevelope mail sent by plane

In most cases, normal envelope mail is not sent by plane. Here's why:

1. Cost: Air transportation is more expensive than ground transportation, so postal services typically use ground transportation for most mail.
2. Distance: For shorter distances, ground transportation is often faster and more efficient. For example, mail sent from one city to another within the same country is usually transported by truck or train.
3. Volume: The volume of mail is massive, and air transportation would be impractical for most mail. Ground transportation allows for more efficient sorting and processing of mail.

However, there are some exceptions where mail might be sent by plane:

1. Long-distance international mail: Mail sent between countries, especially across oceans, is often flown by plane to ensure timely delivery.
2. Priority mail: Some postal services offer priority mail services, which use air transportation to ensure faster delivery. This is often the case for packages or mail that requires expedited delivery, such as time-sensitive documents or gifts.
3. Special services: Some postal services offer special services, like overnight delivery or same-day delivery, which may use air transportation to ensure timely delivery.

In the United States, for example, the United States Postal Service (USPS) uses a combination of ground and air transportation to deliver mail. They have a network of trucks, trains, and planes to transport mail across the country. While most mail is sent by ground, some mail is flown by plane, especially for long-distance international mail or priority mail services.

So, to summarize: while some mail might be sent by plane, most normal envelope mail is transported by ground transportation due to cost, distance, and volume considerations.