Photos: Six European countries where strikes could dampen your travel plans

The travel industry is on high alert for disruption after Europe's peak season last year was hit by cancellations, causing chaos at airports. This summer, air traffic control issues are likely to be the weak spot, according to warnings from Eurocontrol, which manages European airspace. Here is a summary of recent developments:

BELGIUM: Ryanair pilots in Belgium went on strike on July 15-16 in demand of higher wages and better working conditions. Around 120 flights were cancelled and 20,000 passengers affected due to the strike.

BRITAIN: A first round of strikes planned by baggage handlers working with easyJet at London's Gatwick airport has been suspended after a better pay offer. However, strikes planned by around 450 ASC, Menzies Aviation and GGS staff, who work for other airlines including British Airways, are still scheduled to take place from July 28 to Aug 1 and from Aug 4 to Aug 8.

FRANCE: Repeated air traffic control (ATC) strikes in France, related to President Emmanuel Macron's plan to raise pension age, have led to delays and limited flights across the country, causing more air space congestion in Europe.

ITALY: About 1,000 flights were cancelled in Italy on July 15 due to a nationwide airport staff strike. Up to 100% workers participated in the strike. Air traffic control company ENAV has confirmed there will be no strikes in the Italian air transport sector between July 27 and Sept. 5 due to a summer exemption provided for in the industry regulations.

PORTUGAL: Easyjet cancelled 350 flights arriving to or departing from Portugal ahead of a cabin staff strike on July 21-25, the SNPVAC union of civil aviation flight personnel said.

SPAIN: Pilots at Iberia Regional Air Nostrum, who had been striking every Monday and Friday since Feb. 27, went on a daily indefinite strike from June 6 amid a pay dispute. As of July 14, Iberia said on its website some flight routes could be affected.