With the jet. The treadmill will have no effect on the plane other than providing friction on the tires. The wind moving over the wings is what makes it lift off. If the jets can get the wind moving at the necessary speed, the plane will take off straight up until the wheels are off the ground. Then it will shoot forward like a SOB.
As for the truck, reading it again, it could be a semantic battle, since he said the truck carrying that stuff weighed that much, it could be read as this is the weight of just the truck, or it could be read as the weight of truck and cargo.
And since the weight is determined by mass and gravity, the truck would weigh less when they took flight because even though the weight is all still contained, the mass of the birds is not acting on any other participants since they are in the air.
2007 Saturn Aura XR | 1970 Chevy Blazer 4x4 | 1970 GMC 3/4 Suburban 4x4