The airlines Qantas Airways Ltd said it may resume Airbus SAS A380 services within two days after conducting checks following a midair engine explosion. The blowout, which forced a plane carrying 466 people to make an emergency landing in Singapore yesterday, most likely was the result of a “material failure or a design issue,” Qantas Chief Executive Officer Alan Joyce told reporters. “This issue does not relate to maintenance,” he said. “This is an engine issue.”