From when work first started it is already going to take over 3 years to complete the terminal and probably closer to 4, 5 years to complete the rest of the airport and 7 years when the rail link is included and you want to spread the work out even further
The problem with the terminal redevelopment is that it is just like a big jigsaw puzzle. Bits can't be started until other bits are finished. Whole areas of the work have yet to be started so I am thinking 2019 for the completion of the terminal.