NEW YORK, June 12 (Reuters) - Northwest Airlines Corp. (NWAC) will defer delivery of six Airbus narrowbody airliners next year because it has enough planes for expected capacity, Chief Executive Richard Anderson said on Wednesday. Northwest, the No. 4 U.S. carrier based in Eagan, Minnesota, had planned to take 31 narrowbody jets, including Boeing Co. 757s (BA) and Airbus A320s and A319s. Anderson, speaking at a Merrill Lynch presentation which was Web cast, did not specify which types of Airbus would be deferred. Northwest said in April that it might delay receiving some narrowbody jets in 2003. Airbus SAS is 80-percent owned by the European Aeronautic Defence and Space Co. NV (EAD) (EAD), with the remaining 20 percent held by British aerospace and defense industries group BAE Systems Plc (BA). Anderson said unit revenue, a key measure of airline health measured in revenue per available seat mile, fell about 2.5 percent in May, likely a significantly smaller decline than the industry overall. Unit revenue fell about 7 percent in the first quarter from a year earlier "and we expect that positive trend to continue through the summer," Anderson said, adding Northwest expects June unit revenue to be off about 2.5 percent from a year ago. Jamie Baker, an analyst at JP Morgan, recently estimated that unit revenue fell 5.5 percent to 6.5 percent industrywide in May from a year earlier. Traffic remains below normal and fares are relatively cheap following the Sept. 11 attacks. Northwest ran a 13 percent smaller schedule in the first quarter than a year earlier, Anderson said. The airline expects the schedule to be 11 percent smaller in the second quarter than a year ago and 5 percent smaller for the year, he said. "We may actually pull down a bit more (capacity) in the fall depending on what traffic looks like," Anderson said. Northwest reported a $171 million net loss in the first quarter when it had about $2.6 billion cash on hand. It has $2.7 billion in cash right now, Anderson said. Northwest is taking delivery of 757s, starting in July, to replace DC-10-40s used on domestic routes by early September. ©2002 Reuters Limited.