Our esteemed pilot and IL Air National Guard Marathon Team leader just sent me a reply:

"I believe the cost per hour of a tanker is approximately $5000. That
includes everything, and may be higher now due to fuel costs.

However, for a 130k fuel load, 160k airplane, we would burn about 5-6000lbs
of fuel. That is approx. 850-900 gallons, at about $3/ gallon."

So I was a little off. I think my 40K was figuring a full-throttle takeoff (the most fun, of course) with a heavier load (coming back from Guam or Hawaii).

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1992 300D 2.5T
1980 Euro 300D (sadly, sold)
1998 Jetta TDI, 132K "Rudy"
1974 Triumph TR6
1999 Saab 9-5 wagon (wife's)