Marines load ordnance onto an F-35B Lightning II during Operational Testing 1 aboard USS Wasp at sea, May 27. Marines and sailors have been working together since May 18 to assess the integration of the F-35B Lightning II, which is currently on track to replace the F/A-18 Hornet, AV-8B Prowler, and the AV-8B Harrier. By the end of the testing period on May 29, U.S. Marine pilots had flown 110 F-35B sorties from USS Wasp, racking up more than 85 flight hours. - Marines load ordnance onto an F-35B Lightning II during Operational Testing 1 aboard USS Wasp at sea, May 27. Marines and sailors have been working together since May 18 to assess the integration of the F-35B Lightning II, which is currently on track to replace the F/A-18 Hornet, AV-8B Prowler, and the AV-8B Harrier. By the end of the testing period on May 29, U.S. Marine pilots had flown 110 F-35B sorties from USS Wasp, racking up more than 85 flight hours.