The head of the F-35 Lightning II program said that Lockheed-Martin Corp. could start delivering a full fleet of new jets as quickly as Boeing Co. can produce an interim fleet of 18 Super Hornets for the Royal Canadian Air Force. The interim purchase, which was announced by Ottawa late last year and is now valued at $6.4-billion, would be a stopgap for the Canadian military before the full $19-billion replacement in the next decade.