The US Air Force (USAF) is reportedly set to continue the weight restrictions placed on F-35 pilots until 2018.
The decision follows ejector seat manufacturer Martin-Baker's request for additional time to conduct further testing on the ejector seat safety features in the fighters, reported Defense Industry Daily.
Air Force spokesman lieutenant colonel Christopher Karns was quoted by DefenseNews as saying: "The [joint programme office] is working to accelerate the timeline for fixes and a lot of energy will be applied to ensuring this issue is resolved in 2017.
"However, getting this right is the top priority."
The F-35 aircraft is a fifth generation fighter powered with advanced stealth, fighter speed and agility, advanced mission systems, fully fused sensor information, network-enabled operations and advanced sustainment.
International partners in the JSF programme include the UK, Italy, the Netherlands, Turkey, Canada, Denmark, Norway, Australia, Singapore, and Israel.
Lockheed Martin, as the prime contractor, manufactures the forward fuselage and wings of the F-35 aircraft, and is also responsible for its final assembly.
Northrop Grumman manufactures the centre-fuselage, and BAE Systems the aft fuselage and tails. Pratt & Whitney is the prime contractor for the F-35's engine.
The multirole fighter combines stealth, agility and advanced technologies to provide the pilot with situational awareness, lethality and survivability.
They will replace the F-16 and A-10 fleet of the US Air Force and complement the F/A-22.
Image: An F-35 prototype. Photo courtesy of US federal government / Wikipedia.