Heathrow is the top mega-hub airport in Europe and 15th in the world. Nine of the top ten are in America: http://www.oag.com/hubfs/Free_Reports/Megahubs/2016/OAG-Megahubs-Index-2016.pdf
Heathrow is the top mega-hub airport in Europe and 15th in the world. Nine of the top ten are in America: http://www.oag.com/hubfs/Free_Reports/Megahubs/2016/OAG-Megahubs-Index-2016.pdf