… What was stuck in my head was the USAF Galaxies and C-17’s taking off with 20-30% fuel NOT on board. This allows them to put more freight on (To the weight of the missing fuel). Then, once airborne and the MTOW is satisfied, they team up with a Tanker and get a full tank. Great idea.

It adds risk. The additional risk is small enough to be acceptable to the military, but not to civilian airlines or regulators. It’s also expensive. It burns more fuel overall, means you need a stock of tankers, takes up more T/O & landing slots, more ramp space. The military do it because the absolute load is more important to them than the cost. Commercial airlines have other priorities.

I wrote in and suggested that the duty free shopping should be done at the point of arrival. This would save several hundred litres/kg or lbs per flight, not only giving some weight to the personal oxy bottle but save TOW as well. I was rejected out of hand.

I’m in complete agreement with you on this. It’s crazy to fly several hundred kilos of glass, water, alcohol etc. from one airport, to another airport where they probably sell exactly the same goods.