United Parcel Service Inc , the world's largest package delivery service, announced plans on Monday to furlough at least 300 pilots as the very gradual pace of the U.S. economic recovery necessitates further cost-cutting.

The recession weakened UPS's air package volume at the same time as the company retired older aircraft that required three pilots instead of the two needed now across its 267-jet fleet, said spokesman Norman Black.

Even though the economy has begun to turn around, UPS anticipates a very gradual recovery and a continued need for belt-tightening, said UPS Airlines President Bob Lekites.

Under the company's contract with its pilots' union, the Independent Pilots Association, furloughs are a temporary but indefinite layoff implemented according to seniority.

Should the company start to add flights in response to an increase in demand, the furloughed pilots will be brought back, again according to seniority.

The furloughs will be implemented in phases, with the first 170 in May.

UPS shares were down .7 percent at $56.82 in afternoon trading on the New York Stock Exchange.

(Reporting by Helen Chernikoff; editing by Leslie Gevirtz)