A worker from United attends to some customers during their check in process at Newark International airport in New Jersey , November 15, 2012. REUTERS/Eduardo Munoz

SAN DIEGO (Reuters) - United Continental Holdings UAKL.N is interested in buying second-hand aircraft as they are released to the market when leases expire, Chief Finance Director Andrew Levy said on Tuesday.

Speaking at the ISTAT Americas air finance conference, he also ruled out United, which recently retired its Boeing 747 jumbo jets, buying any more aircraft in that category for the world’s largest four-engined jets.

United, the largest U.S. carrier by traffic, has been tipped in the past as a potential buyer for the Airbus A380 superjumbo.