References to the SR-71. Both the U-2 family and the SR-71's use (or used) JP-7. The reason for this special fuel is that at the altitudes these airplanes operate (or operated) their range would be restricted by the evaporation rate of the fuel (JP-4). So a fuel with a very low vapor pressure (JP-7) was developed. This fuel is also very difficult to light off; I know the SR-71's used a hypergolic (spelling?) ignition system in which a fluid, that ignites on contact with oxygen, is injected into the burner section (and the afterburner or reheat to Brits) and this ignites the fuel. If you see a film of either an engine start or an A/B light of a SR-71, look for the green flash before ignition. That is the hypergolic fluid lighting off. I don't know what type of ignition system the U-2's use.
KC-135's and KC-10's were adapted to carry this fuel. The KC-135Q is the SR-71 refueler.
I would still like to get some tanker stories, if anyone has some.