US Deputy Defense Secretary Bill Lynn said the delivery of the first joint strike fighter (JSF) to Australia would now be executed closer to the original deadline.
Lynn said development delays on the JSF programme has been shortened from 30 months to about 12 months.
The first delivery of JSF to Australia was delayed by a year, after the US defence secretary Robert Gates removed Major General David Heinz from the JSF project.
Gates also withheld $614m in payments from Lockheed, the prime contractor of the programme, in order to help fund further development.
"The development was definitely going to cost more and the unit costs have gone up and the important thing is to get it right and budget it right and that's what we think we've done," Lynn said.
Australia, which is to acquire 14 F-35 fighters to replace its aging fleet of F-18 Hornets and F-111s at a cost of $3.2bn, will later increase the numbers to 100, at a projected cost of $16bn.
A fifth-generation, single-seat, single-engine stealth multirole fighter, the JSF, also known as the F-35, can perform close air support, tactical bombing and air defence missions.