Delta said it also expects the MD-90 aircraft, which are made by Boeing Co. BA, +0.84%subsidiary McDonnell Douglas, to exit its fleet in June. Boeing's stock fell 2.3% ahead of the open. Delta expects to record impairment charges of $1.4 billion to $1.7 billion as a result of the aircraft retirements. Delta said the 777 fleet included 18 aircraft. Chief Executive Ed Bastian said the decision was made as international travel is expected to return slowly. "[P]arking this fleet will provide significant cost savings over the next several years," Chief Executive Ed Bastian wrote in a memo to employees.