Burlington Northern Air Freight to lease 13 jets.

The Irvine-based subsidiary of Pittston Co. said the McDonnell Douglas DC-8 and Boeing 707 aircraft are valued at about $100 million and should be operational in the calendar fourth quarter. Burlington plans to refit the obsolete passenger jets with new engine covers to reduce noise levels, which led to them being barred from many airports, according to George Ryan, the firm’s president.