How do I make multiple meshes in the same script?

Hi, I am trying to generate a series of planes between markers that the player can place in the game world, I've got code to generate the meshes but the last mesh is the only one that ever shows up, I've tried naming them and tried to set them as different game objects with no success, I was just wondering if anyone could help me out, this is my first C# project so I'm hoping I've just missed something simple:

 while (planeNo < markerNo)
             {
                 MeshFilter meshFilter = GetComponent<MeshFilter>();
                 if (meshFilter == null)
                 {
                 print("MeshFilter not found bro!");
                     return;
                 } 
                 markerStartX = (GameObject.Find("Marker "+planeNo).transform.position.x);
                 markerStartZ = (GameObject.Find ("Marker "+planeNo).transform.position.z);
                 planeNo ++;
                 markerEndX = (GameObject.Find ("Marker "+planeNo).transform.position.x);
                 markerEndZ = (GameObject.Find ("Marker "+planeNo).transform.position.z);
                 
                 
                 Vector3 p0 = new Vector3(markerStartX,0,markerStartZ);
                 Vector3 p1 = new Vector3(markerStartX,buildingHeight,markerStartZ);
                 Vector3 p2 = new Vector3(markerEndX,buildingHeight,markerEndZ);
                 Vector3 p3 = new Vector3(markerEndX,0,markerEndZ);
                 
 
                 Mesh mesh = meshFilter.sharedMesh;
                 //mesh.name = ("Mesh "+planeNo);
                 if (mesh == null)
                 {
                 meshFilter.mesh = new Mesh();
                 mesh = meshFilter.sharedMesh;
                 }
                 mesh.Clear ();
                 mesh.vertices = new Vector3[]{p0,p1,p2,p3};
                 mesh.triangles = new int[]
                 {
                 0,1,2,
                 0,2,3,
                 2,1,3,
                 0,3,1
                 };
                 
                 mesh.uv = new Vector2[4];
 
                 mesh.uv[0].x = 0; mesh.uv[0].y = 0;
 
                 mesh.uv[1].x = 1; mesh.uv[1].y = 0;
 
                 mesh.uv[2].x = 0; mesh.uv[2].y = 1;
 
                 mesh.uv[3].x = 1; mesh.uv[3].y = 1;
                 
                 mesh.RecalculateNormals();
                 mesh.RecalculateBounds();
                 mesh.Optimize(); 
                 meshNo ++;
                             
             }