Queuing Nodes

I am trying to make a basic program for an Air traffic controller to land planes as the come in using nodes but i cant get the nodes to order properly as when i add a new one in it deletes the first node.

here is my code for the ordering of the nodes.

Code:

public void addPlane (PlaneNode planeIn) { if (start == null) { start = planeIn; end = planeIn; planeIn.setNext(null); planeIn.setPrevious(null); end = start; System.out.println("Thank you the plane has been added"); System.out.println(planeIn.toString()); } else { // if(end == start ){ // // get the lastNode in queue // PlaneNode currentFirst = new PlaneNode (); // currentFirst = this.getEnd(); // currentFirst.setNext(planeIn); // planeIn.setPrevious(currentFirst); // planeIn.setNext(null); // end = planeIn; // System.out.println(currentFirst.toString()); // System.out.println(planeIn.toString()); // System.out.println("Thank you the plane has been added1"); // } else { // // if already nodes in queue // get the lastNode in queue PlaneNode currentLast = this.getEnd(); // current update currentLast.setNext(planeIn); // new plane update planeIn.setPrevious(currentLast); planeIn.setNext(null); // update queue's last value to point to new plane this.end = planeIn; System.out.println("Thank you the plane has been added2"); } }

The add planeIn PlaneNode works fine. Any help would be great. Thanks
Matt