[pram]

I was an inflight-refueling technician in the USAF and there was a variant of the tanker (KC-135T) that had isolated tanks to specifically carry this stuff, for refueling an SR-71. Sadly that was before my time. A neat little factoid tho, I guess.

[savoytruffle]

Wikipedia indicates it was originally KC-135Q with the unique fuel system (which separates the exotic SR-71 fuel payload from the typical fuel to fly the refueling plane). KC-135T was the re-engined variant using modernized engines like the rest of the fleet.