I don't know about UPS specifically, but: If you consume more than about 1,000 gal/month, you'll buy your gas from a "cardlock" gas station. The station typic

I don't know about UPS specifically, but: If you consume more than about 1,000 gal/month, you'll buy your gas from a "cardlock" gas station. The station typically has no attendent and no services other than a gas pump, and requires minimum monthly purchases. If you consume more than 50,000 gal/month at a single fleet depot, you'll get a tank and buy the gas by the truckload - the equivalent of what an independent gas station does. If gasoline consumption is a large enough fraction of your total spending, and you're big enough, you'll buy gasoline futures directly from the folks who peddle in them; or buy it directly from the refineries. You'll have this gasoline delivered to the tanks at your depot. If you need to use a third party's tanks, you'll deliver it directly to their tanks. For example the FBO (gas station) at my local air port refuels four Sky West/United flights a day, in addition to the occasional private jet and lots of 100LL to the general aviation crowd. If they put jet fuel in your Citation X, you need to give them a bunch of money, some of which they use to buy more jet fuel. When they put jet fuel in a SkyWest plane, SkyWest delivers more jet fuel to them and pays a nominal fee for their storage and pumping services. Federal Hours of Service rules limit the UPS drivers to 11 hours of driving a day. If you assume a UPS truck gets 8 miles/gal and averages 45 mph, then a 75 gallon tank is enough for all day, and they would only need to refuel at the depot.