So how does a flying aircraft produce lift, or a prop thrust, if its not by accelerating the air mass in the required direction.
I have already explained how propellers create thrust and how wings create lift. They both exert a force on the air in one direction and the air exerts an equal and opposite force in the opposite direction. Unfortunately this process causes the air to accelerate creating propwash from the prop and downwash from the wing. But these movements of the air are not the means by which the thrust and lift were created. They are the unfortunate side effects.
You saying NASA don't know what they're talking about?
I am not saying that NASA (and many authoritative text books) don’t know what they are talking about. I am saying that they have chosen the explanations which best fit their purposes. As I have said before, there is a clear relationship between the accelerations and the thrust/lift generated and numerous equations and analytical methods are based on this relationship. Any text which goes into these equations and methods is best served by starting with the idea that the accelerations produce the forces.
PS: Scenario 2, you are confusing aerodynamic lift with buoyancy.
I am not confusing the two, I am comparing them. To see if this comparison is valid we need to look at how buoyancy really works. Let’s imagine that the balloon is rectangular in shape (this just simplifies the descriptions).
If we assume still air conditions and ignore any meteorological factors, then the static pressure at any point in the atmosphere is determined by the mass of the column of air above that point.
Let’s consider two columns, the one immediately above the bottom of the balloon and one immediately adjacent to it.
For any position immediately adjacent to the bottom of the balloon, the column above will be entirely made up of air, which will exert a certain static pressure.
For the column directly above the bottom of the balloon, most of the column will be occupied by air but some will be occupied by the balloon. The balloon is filled with helium which is less dense than air, so its overall density will be less than that of air. This means that the static pressure which this column is able to exert at the bottom of the balloon will be less than that immediately adjacent to it.
Air moves from areas of high pressure to areas of lower pressure, so the air surrounding the bottom of the balloon will tend to move under the balloon, thereby increasing the local static pressure. We now have a situation where the static pressure pushing upwards at the bottom of the balloon is greater than that which can be exerted by the column of air plus helium balloon above. Unless the balloon is tethered it will move upwards. So we have an upward acting lift force which is being generated without the need for any acceleration of the air.
Scenareo 3, the motor vehicle does accelerate the earth in the opposite direction to that of its travel. Due to conservation of momentum, every force on the Earth’s surface has some effect on its rotation. The gradual slowing of the earths rotation is caused by wind friction, not tidal forces as previously thought.
That sounds plausible but let’s look a bit more closely to test your argument. Your car is driving north at 70 mph. So by your argument you are accelerating the road towards the south. But at the other side of the road my car is driving south at the same speed. By your argument I am accelerating the road towards the north. But the road cannot be simultaneously accelerating north while also accelerating south. If we ignore the fact that I am probably a bit fatter than you are (believe me I am), these two accelerations must be equal and opposite, so they will cancel to zero. So we are both generating thrust but there is no acceleration going on.