When I have seen a video on YouTube of a car racing an airplane, they do not add nor subtract to account for rotational speeds of the earth, they just clock the speed the plane is going.
That is due to the fact that planes and cars are not subject to the rotational speed of the earth, which is based on measurement from outside of the earths atmosphere. Both cars and planes are subject to the atmosphere and
earths simultaneous rotational speed as measured from the ground and contained within the earths atmosphere.
PS, you obviously have an agenda here, regardless of how ignorant your claims may be. Why don't you just come out with what it is you believe and we can move on, either disregarding it as foolishness, or looking deeper into the subject, but whatever you decide, please stop with "planes flying in opposite directions must be travelling at different speeds", your assertions are ludicrous.