so AA took one of the JFK - LHR slots.
And started service from JFK to STN. So, broadly speaking, as one frequency drops from LHR, frequencies build up from STN (I appreciate that isn't the
exact timetable, but it is more or less what is happening).
Whatever the reasons behind the move it doesn't take away from the fact that JFK-LHR loses a frequency and STN ultimatley picks up two.
So my original point still stands, that now one JFK-LHR 777 is being dropped, JFK-STN is not going to become a single class 757 route because there would be a lot of premium demand needing soaking up that would go elsewhere.