It depends on what you are trying to achieve. If you would like to simulate the airflow around this plane in a narrow space or corridor, then your mesh is correct! But, if you would like to simulate the airflow around the plane as if it were flying in open space, then we need to make some changes. When doing an external flow simulation in open space, you want to make sure that you have a lot of room behind the model and to the sides of the model. Like below.
There is a general rule of thumb. 7-10 X the size of the model behind it, and 3-5 X the size of the model to each side of it. Does that make sense?
That way, you are sure to collect the right data, as the airflow will behave differently in a closed space than it would in an open space. So it really depends on what you are trying to simulate.
I also did some meshing refinements around the edges of the plane to get the nice and neat. You can see what I did with this project, and look at SimScale Mesh 2.
I hope that this helps