Airmail envelopes are preprinted with a red and blue airmail border. T...
Airmail envelopes are preprinted with a red and blue airmail border. To save on postage costs for international mailings, airmail envelopes are constructed with lighter weight materials.
If used domestically, airmail envelopes will not receive preferential handling or meet USPS (United States Postal Service) OCR (Optical Character Reader) requirements.