Washington ? An improving economy means the Postal Service will handle 20 billion letters, packages and other items being sent to relatives, friends and Santa Claus this holiday season.

“Generally that economic news translates into additional volume for us,” Postal Service chief operating officer Patrick Donahoe said. “We’re expecting a very successful season.”

Donahoe said they had already seen a 1 percent increase in volume compared with the 2002 holiday season, and he expected that to go higher.

The 20 billion pieces of mail expected to flow through the Postal Service system this season represent a 50 percent increase in postmarks compared to the rest of the year. The heaviest mailing day should be Dec. 15, with 850 million to 900 million letters and packages going out. The busiest delivery day would follow two days later.

To put it into perspective: The Postal Service’s average of 670 million pieces of mail a day would circle the globe three times, but Dec. 15 could add another lap around.

Air cargo capacity will be increased by nearly 40 percent two weeks before Christmas, and hundreds of trucks will be added.

Post offices will be open later in the evenings and on weekends, including Sundays, during December.

However, the Postal Service plans to hire only 10,000 temporary employees, half as many as last season.

United Parcel Service and FedEx are making similar preparations.

To ship an estimated 300 million packages this season, UPS scheduled additional and late pickups for peak days. The parcel company is also adding nearly a dozen large jets to its air fleet, and will hire more than 50,000 temporary employees.

FedEx expects its average daily package volume to increase by around 20 percent and plans to hire several thousand people to help with the additional load. On its busiest day, Dec. 15, the company expects to handle around 7 million packages.

Among the 2.8 billion holiday stamps the Postal Service is printing this season are images of a horn-playing Santa on roller skates and reindeers in suspenders. Other stamps celebrate Hanukkah, Kwanzaa and the Islamic holiday of Eid al-Fitr, and all will be available at 82,000 locations around the country, including 38,000 post offices.