Combined Joint Expeditionary Force, with land, sea, and air components
Cooperation on the Future Strategic Tanker Aircraft: The French armed forces may pay to use an Airbus A330 MRTT if there is spare capacity.
Possible cooperation in Afghanistan
Cooperation on aircraft carriers: Interoperability improvements, so warplanes from either country (F-35C Joint Strike Fighters and French navy's Dassault Rafales) could use each other's aircraft carriers.
Joint development of new technologies for nuclear submarines
Shared support for A400M fleets, including training
Sharing of military communications satellites
Coordination of nuclear tests, and cooperation between Aldermaston and Valduc.
Unmanned air vehicles, including the BAE/Dassault Telemos
Entente frugale Wikipedia
Entente frugale is a term for cooperation between the British and French governments, particularly in military procurement, which is driven by cost constraints, which was announced in November 2010 as part of the Lancaster House Treaties.
The name is a wry reference to the Entente Cordiale of 1904.
Together, France and the UK account for half of all military spending in the EU, and two thirds of research and development.