Just a glance at KLM's route map, below, demonstrates how efficient a hub it is as it and its base at Amsterdam Schiphol compete amongst the so-called FLAP airports with Frankfurt, London Heathrow and Paris CDG and their carriers for the 'old world' hub title in Europe as opposed to the 'new world' ones in the Middle East and Turkey.
MAP- Amsterdam Schiphol is currently directly linked to 259 destinations, heavilly dominated by its strong European network
Source: CAPA - Centre for Aviation and OAG (data: w/c 07-Oct-2019)
Or perhaps that should be FLAPM in the light of Munich airport's rise to become one of the top five international airports in terms of hub connectivity, behind Heathrow, Frankfurt, Chicago O'Hare International and Schiphol.
That KLM route network is focused and centralised on Amsterdam's immediate region - Europe - more than that say of Emirates' network in its locality or even Turkish Airlines' one. KLM knows where its bread is buttered and that is in highly-populated areas of northern Europe in particular where it can duplicate the role of the national carrier and even enhance it for those living far from its own national airline's hub.
Mr Elbers' selection of Cardiff airport in the UK as his example is apposite. Cardiff is one of no less than 17 airports KLM serves in the UK from Amsterdam and both it and Schiphol long ago established themselves as the 'alternative London airport' for UK residents who would otherwise have few travel options other than to travel from or via Heathrow.
And the 'via' bit has become increasingly more difficult. British Airways serves only seven UK domestic points from Heathrow and for all the pontificating about protecting slots for domestic routes once the third runway is built (it is competing with the HS2 rail project and Brexit for which will take the longest) that doesn't look like it will change substantially anytime soon.
That network also partially enables Cardiff airport to claim on its website that it offers '50 direct flights and '900 connections', also by way of services to Paris CDG, Doha and Dublin, where Aer Lingus has been attempting to replicate to North America what KLM does globally, benefitting from a US customs and immigration pre-clearance station which Schiphol also covets. In fact, Cardiff airport's 'direct' route map draws striking similarities with KLM's.
Schiphol's continuing success with this hub traffic means that capacity has become a serious issue. In the last 12 months the prospect of the airport being extended out towards the sea (which at its closest point is about 20km/12.5 miles away) has been proposed
https://corporatetravelcommunity.com/amsterdams-schiphol-airport-is-all-at-sea-over-its-extension/
Now the Dutch House of Representatives has held a hearing with industry experts to investigate strategies for such expansion. Speaking at the hearing, a PosadMaxwan (an urban design agency) engineer estimated the cost of seawards expansion at between EUR33 billion and EUR46 billion, while such expansion would compete with interests of fishing, shipping and renewable energy industries in the North Sea. Read: It probably won't happen.
But something has to be done. The opening of Lelystad airport, about 50km/31 miles to the northeast of Amsterdam for commercial activities on 01-Apr-2020 has been postponed again due to legal issues with nitrogen deposition affecting all major infrastructural and agricultural activities in the Netherlands.
Even while passenger traffic growth has tailed off over the last two years as it has elsewhere on the continent a resolution needs to be found to the capacity problem or Brazilian, Japanese and Chinese residents of Tiger Bay will be looking for new ways to get home.
CHART - Amsterdam Schiphol Airport passenger numbers, 2012 - 2019
Source: CAPA - Centre for Aviation and Amsterdam Schiphol Airport reports