Delta is grounding its entire fleet of 14 B747-200 freighters by the end of this year, to stem growing losses from its cargo division.
The US airline said the decision was made due to the age and inefficiency of the fleet ¨C operated by Northwest Airlines, which Delta acquired last year.
Cargo revenue dropped 44%, or US$146m, in 2008, reflecting "significant weakness in demand and yields due to the global economic recession and declining fuel surcharge revenue ¨C as well as reductions in dedicated freighter capacity."
The Northwest freighter fleet, which operates mainly on the transpacific market, is the only significant freighter fleet operated by a major US airline.
Delta completed its acquisition of Northwest in October 2008, creating what by some estimates is the world's largest airline.
Delta last week posted a first-quarter net loss of $794m.
It said it generated $100m in merger-related synergies in the first quarter.