Sources: USPS. UPS and FedEx, Annual Reports. Packages shipped by FedEx Ground and FedEx Express. UPS involves US domestic parcel operations. First-class mail is used for postcards, letters, large envelopes, and small packages weighing less than 13 ounces. Total mail volume includes standard mail (or bulk), usually consisting of flyers, … Continue reading Mail Carried by USPS and Parcels Carried by Major Carriers, United States, 2004-2022