Even in the lightning-fast digital age, individuals and businesses rely on postal mail to send packages, letters and documents. Both the U.S. Postal Service and private shipping companies offer ground mail and airmail services. There are several differences between these services, and which one is optimal for you depends on your budget and mailing needs.

Cost

Airmail is generally more expensive due to the costs involved in transporting packages via aircraft. Ground mail, conversely, tends to be the cheaper alternative. Specific pricing varies widely depending on destination and package size. According to "Consumer Reports," an overnight air shipment that would cost about $73 with FedEx or UPS would cost only $10 if sent over the ground.

Efficiency

Airmail offers efficiency and quickness of delivery. Both the USPS and UPS offer overnight airmail services which, while more costly than ground shipping, can guarantee a package's arrival in a short span of time. Accordingly, urgent deliveries and perishable items are more typically sent via air. Ground shipping is slower and generally takes one to five business days, depending on distance.

Transport Method

Airmail, as the name implies, involves loading parcels onto airplanes that fly to mail depots, where the parcels are distributed to their addressees. Companies such as DHL have their own aircraft for shipping items nationally and worldwide. Ground mail, alternately called "surface mail," transports parcels over land, typically in trucks and other vehicles. The USPS, for example, covers millions of miles annually in driving distance.

Destination

Ground mail is better suited to mailing packages and letters within the United States. Airmail, however, is the standard method for international deliveries by USPS, FedEx and UPS, because airborne transport covers vast distances in shorter periods of time. While international ground shipping exists, it can take an inordinate amount of time for a package sent, for example, from Russia to the U.S. to traverse both land and sea.