The nation's third-largest airline, which has warned of the possibility of a bankruptcy filing, said Thursday the agreement with Memphis, Tenn.-based FedEx Corp.'s Express division also calls for the sale of four spare engines for delivery in 2004, besides the McDonnell Douglas MD11 aircraft.

Terms of the deal were not disclosed. Delta said the agreement is subject to certain conditions, which it did not specify. Spokesman Scott Brittain said he could not elaborate beyond the company's statement.

"The contemplated sale furthers Delta's fleet simplification plans and is part of the airline's overall transformation plan," said Michael J. Palumbo, Delta's executive vice president and chief financial officer.

Besides seeking deep wage concessions from its pilots and trying to restructure its heavy debt, Atlanta-based Delta also has been reducing its fleet obligations in recent months.