The hell it don't. They also contract with the other Parcel Carriers to carry their mail.
Key Details on USPS Air Transportation:
Contractual Partners: In April 2024, the USPS signed a 5.5-year contract with UPS to manage air cargo, shifting much of the volume away from FedEx.
Mail Types: Air transport is used for First-Class Mail, Priority Mail, and Priority Mail Express.
Shift in Strategy: The USPS has been actively reducing its reliance on air transport to cut costs, moving more than 95% of First-Class mail and packages via ground transportation.
Special Cargo: FedEx is still used for specialized air shipments, such as hazardous materials, perishable items, and live animals.
While the USPS has significantly reduced air cargo volume to save costs, air transport remains a crucial component for long-distance, fast-delivery mail.