CHARLOTTE, N.C. -- Among the assets US Airways ( LCC) would bring to a merger is one that its potential partner totally lacks -- an aircraft order. If United ( UAUA) were to merge with US Airways, it would gain access to an order for 92 narrowbody and widebody Airbus aircraft, with a list price around $10 billion, making the France-based airplane maker a likely winner if the two carriers successfully complete a deal. That would mean Airbus could become the primary supplier for one of the two biggest U.S. airlines, a position it has never occupied. The jury is still out, however, on whether Boeing ( BA) or Airbus would benefit more from a proposed merger between Delta ( DAL) and Northwest ( NWA). Delta has been a Boeing customer, while Northwest's big jet fleet is divided between planes made by Airbus, Boeing and McDonnell-Douglas, now part of Boeing. Delta CEO Richard Anderson has indicated the combined carrier would order from both manufacturers. One thing is certain -- there is little unity in the fleets. Among the approximately 450 large jets at Delta and the 300 at Northwest, the only common aircraft is the Boeing 757, of which there are about 200. The combined fleet, says Teal Group aviation analyst Richard Aboulafia, would include "a plane for every occasion." In the industry downsizing that took place after Sept. 11, many carriers used the opportunity to increase the commonality of their fleet types by shedding airplanes, but there has been no indication so far that a combined Delta and Northwest would follow that trend.