I never know about a second tunnel connecting to a new road through the back of the airport.
Next month the airport will put out for consultation a selection of plans and ideas to expand the airport outside its boundary for up to 38 million passengers both to the north and south of the runway. As I have mentioned on many occasions there is a large chunk of land south of the runway that is inside the Luton town boundary that is flat and level with the runway by Someries Castle.