MPS strongly criticised the Ministry of Defence (MoD) over the "flawed" decision to switch fighter aircraft for the Royal Navy's new carriers.
The Commons defence committee said a decision in 2010 to switch carriers, which was then rejected, was a mistake that led to increased costs and delays to the carrier programme.
The government said in their 2010 Strategic Defence and Security Review that it would adopt the carrier variant of the US-built F35 Joint Strike Fighter rather than the jump jet version chosen by the previous Labour government.
However Defence Secretary Philip Hammond did and U-turn last May and said that the MoD would revert to the jump jet version amid fears of spiralling costs.
Prospect union national secretary Steve Jary said: "Prospect has always said the Strategic Defence and Security Review was driven by cuts rather than a rational assessment of the country's strategic defence needs."