Air controllers at their desks. | Rafael_Garcia_

Air traffic delays in Europe more than doubled in the first five months of this year over 2017, according to European air traffic management body Eurocontrol.

On average 50,000 air passengers a day in Europe are suffering delays to flights of one to two hours, Eurocontrol revealed.

But it warned that figure could rise ten-fold to almost 500,000 a day within 20 years.

Eurocontrol reported air traffic rose 3.4 % year on year in the first five months of 2018, but ‘air traffic flow management’ delays increased from an average 0.46 minutes per flight to 1.05 minutes.

Airlines including British Airways-owner IAG, Ryanair, easyJet, Lufthansa and Air France-KLM have hit out over delays caused by strikes by air traffic controllers.

But the biggest causes of delays were under staffing and under-capacity.

Eurocontrol reported 45% of delays are due to staffing and capacity issues – “notably in Germany, France and the Low Countries – and 28% due to “disruptive events such as strikes”.

Eamonn Brennan, Eurocontrol director general, warned of increasing congestion if “serious capacity issues” are not addressed.

In an address to the general assembly of airport association ACI Europe this week, Brennan said: “Europe is already struggling to cope with the levels of traffic.

” He said growth of 1.9% a year between now and 2040 is “our most likely scenario”, meaning an additional 16.2 million flights a year.

Brennan said: “Many airports will become much busier, with higher delays. We need to address the issue as a matter of urgency.

” He forecast the number of passengers delayed one or two hours “will grow to around 470,000 a day in 2040”.

ACI Europe director general Olivier Jankovec said: “People cannot continue to presume that air traffic growth and the economic benefits that come with it can happen without a corresponding increase in airport capacity.”