Achim Martinka, the carrier’s vice president for the Americas, said LC was looking for six “MD-11 equivalent” freighters and would announce its decision by the end of March.

LC has returned almost to its pre-recession volumes after a 20 percent increase last year. It has returned all 18 of its MD-11s to service after grounding a number of aircraft in 2008-09.

Airlines laid up large number of freighters during the economic downturn, but many older, less fuel-efficient models, such as Boeing 747-200s, are unlikely to come back into service. The rapid recovery of the market means the surplus in global capacity will narrow to 1 percent this year, but LC has calculated there will be a deficit by 2012 and a 5 percent capacity shortage by 2014.

Martinka ruled out further MD-11s, telling a media briefing in New York, “We need a more economical, environmentally friendly aircraft.”

He said Lufthansa could convert existing passenger B747-400s or acquire B777 freighters. It has no 777s in its passenger or freighter fleets, but AeroLogic, the LC/DHL joint venture, operates 777Fs exclusively. Martinka said Lufthansa Cargo was “quite happy with the experience."

He added that LC may return to wet-leasing freighters, as it did before the downturn, to cover any shortfall in capacity ahead of new aircraft being delivered.