The U.S. Postal Service spent about $3 billion to transport mail via air in fiscal year (FY) 2021, an increase of about $53 million over FY 2020. These costs consisted of contracted services from [redacted], commercial airlines, [redacted], auxiliary transportation, supplemental ad hoc charters, and terminal handling services (THS) operations.
The air network relies on Postal Service processing facilities to tender mail timely and to use volume arrival profiles (VAP) to support efficiency in THS operations. The VAP details the hourly percentage of mail Postal Service facilities are required to deliver to THS facilities while still allowing THS personnel enough time to prepare and tender the mail to the appropriate airline.
Source: USPS Office of Inspector General