Use layers. Place each row of planes on its own layer and its trail on its own layer. Then you can move the layers so the planes are on top of the trail. Since the trails are on their own layers, you can then change its opacity as it is layer based.
layer 1 - first row of planes
layer 2 - trails for first row of planes
layer 3 - second row of planes
layer 4 - trails for second row of planes
etc
etc.