I think we all need to remember that it takes a certain amount of energy to move the mass when operating any vehicle, car, truck, boat or airplanes.
The faster you go the more fuel it will use and the quicker it will get to where you want to go
I remember talking to some SCTA (Southern CA Timing Assoc.) land speed racers at El Mirage on how fast they could make cars stock street go back in the mid 1970s, the replies were anyone can go 125 MPH, some can go 150 MPH but once you get above a certain speed, usually 150 MPH, you have to double the HP to go 175 MPH in the same car with no other changes
I had that example made to me while flying my 1960 Piper Comanche 250 home too SO CA from the Tacoma ,WA area after visiting our grandkids. I was flying at 11,500 above a solid cloud cover, the outside air temp was right at +5 F, I had the airplane trim out to fly straight and level at 2400 RPM with the mixture set at 50 F rich below peak EGT, the ride was very smooth and basically boring so I thought I will try slowing the prop RPM down to try and save some fuel, I use the prop controller to slow it down and then retrim and reset the mixture for that RPM and that stupid dang airplane went from 148 knots ground speed up to 162 knots I didn't believe that at all so I redid that test twice in the next 20 minutes, it repeated Got their faster and saved fuel, went from 10.0 GPH to 9.6 GPH at 13 knots quicker ground speed
I am not a weather guru or know anyone who is but I ended up thinking that the colder denser air at that altitude that day was pushed more efficiently by my prop at 2300 RPM versus 2400 RPM
Testing paid OFF
Your right foot determines the fuel mileage, a vacuum gauge can help you get the best mileage on long trips by using the lightest pedal pressure you can to maintain the speed you want to go that day on hat trip