The operation of Egypt's Cairo International Airport was gradually returning to normal on Friday after dozens of fights had been delayed, diverted or cancelled due to a strike of air traffic controllers.

"The operation came back to normal at about 8:00 a.m. today. Most of the stranded travellers have boarded in the morning," said a customer service representative at the airport.

But quite a few flights were still affected on Friday.

According to the airport's display screen at 4:00 p.m. on Friday, eight flights, mostly bound to Europe, were delayed.

"But the strike hasn't totally ended yet, meaning that some flights may still be put off," Sherif Nabil, agent of EgyptAir, told Xinhua at the airport.

Air controllers began to strike late night on Wednesday but ended after some hours. According to some Egyptian media, the protest was triggered after a pay increase for air traffic controllers was cancelled when other staff protested against it.

A meeting is expected to be held on Saturday to discuss the demands of the protestors, according to a senior aviation official on Thursday.