No. It's enough to write "Par Avion - By Airmail"clearly in the top left hand corner of your envelope.
Any US postage stamp is valid for Air Mail. It is important to mark the envelope correctly. And the stamps used must have a value on them, you cannot use Forever Stamps.
Yes, the air mail stamp is still valid for postage in the US. Just equal or exceed the cost of mailing the item.
Yes, but you may pay more to mail the package if it only weighs one ounce, and you use a one ounce Airmail stamp.
No. When mailing items you use the stamps of the country of origin.
No, you have to use stamps from the country of origin of the mail. In this case you will have to use Italian postage stamps.
Yes, every country uses postage stamps.
Of course you can. As long as the total amount of postage equals the first class rate. All mail is sent air these days.
You can use any USPS postage as long as it is at least $0.94. Make sure to write "AIRMAIL" on the letter as well.
England as the first to use postage stamps, starting in 1840.
The entire purpose of the Forever Stamps was that you can use them for one ounce of First Class Postage forever. No additional postage is necessary.
ofcourse they do
You can use forever stamps for an ounce of postage forever. They never lose their value for one ounce of postage.
They are still valid for use as postage as long as they add up to the proper postage. If you check USPS regulations Postage due, special delivery and certified mail stamps are NOT valid as payment for postage.
Yes, that is what you would use. The stamps need to be from the country of origin. The Universal Postal Union coordinates between countries.