The F-111 was originally designed for use by the USAF and the USN, and was meant to be a money saving measure by then Secretary of Defense Robert S. McNamara. This one platform for multi-service use was not well received. One of the biggest problems that both services had was weight. The Navy also wanted it for use with the Phoenix missile. The issues that the USN had with the "Vark" just became to numerous and another famous aircraft was created, the F-14.
Even though the F-111 started out on a rocky road, it would eventually turn a corner through the hard work of the developers & the crews and become one most important aircraft of the Vietnam War and several modern day operations. Australia was the only other country to use the F-111 and had originally intended them to stay in service to the year 2020. Due to increased maintenance issues and fiscal impact, Australia retired the F-111 in 2010.