The Royal Air Force has an interesting way of doing things. The are just getting a brand new 14 aircraft fleet of Airbus A330 jet tankers into the RAF. Or sort of. The aircraft are owned by a "private" company called AirTanker . This company is authorized to rent, loan, or lease these shiny new tankers out to other EU countries when they are not needed by the RAF. For instance just last month, France found itself way short of tankers to support their Mali operation.
This sort of thing has been going on long enough for the various EU air forces to define a "Standard C130 Flying Hour" as a unit of account. One flying hour from an RAF jet tanker will be worth three Standard C130 Flying Hours. Borrow my nice new A330 tanker for one hour and you owe me three C130 flying hours.
And the Brits have yet to accomplish some Brit paperwork needed in order to actually refuel in the air. Each warplane type (F16, Tornado, Grippen, whatever) needs paperwork before air to air refueling can be done. This has gotta be some kind of Euro job security system. In USAF all warplanes refueled off the KC-135's, here now and forever. There was no paperwork to accomplish on a type by type basis.