When the Cold War ended the service had well over 500 vessels in the active fleet, but that number dwindled to less than 400 during the 1990s and less than 300 in the decade just ended.

FORBES: Low-Cost Warship Rescues Navy From Shrinking Fleet

The Air Force announced earlier this week that it is grounding a third of its active-duty fleet through September 30 due to a shortfall in funding driven by the need to bring spending into compliance with the deficit law.

FORBES: Pentagon Budget Request Sticks With Obama Priorities, Ignores Deficit Law

On Endeavour's return, the only active ship left in the US space agency's (Nasa) shuttle fleet will be Atlantis.

BBC: Shuttle Endeavour launches one last time