: Dozens of flights, mostly of Qatar Airways, were grounded across the region on Tuesday
Saudi Arabia, the United Arab Emirates, Bahrain and Egypt have closed their airspace to Qatari aircraft on Tuesday amid a deepening diplomatic row, forcing Qatar's flag carrier to re-route its flights over Iran, Turkey and Oman.
The decision by the four Arab nations to sever diplomatic ties and cut off sea and air links with Qatar has caused major disruptions to air travel across the Gulf and raised fears for the future of aviation in the region,
The countries that launched the measures against Qatar have accused it of supporting "terrorism", a claim Qatar has called "unjustified".
More than 70 flights were grounded across the region on Tuesday, according to data from scheduling firm OAG. A majority of the flights belong to Qatar Airways.
Other airlines affected include Dubai's Emirates, Abu Dhabi's Etihad Airways, Saudi Arabia's Saudia, and Bahrain's Gulf Air, which have all cancelled flights to and from Doha.
Alexandre de Juniac, the director general of the International Air Transport Association (IATA) has expressed concern over the blockade and called for more openness.
"We would like borders to be reopened, the sooner the better," he told reporters at the group's annual meeting in the Mexican city of Cancun on Monday.
The departure terminal at Doha's Hamad International Airport was virtually deserted early on Tuesday. More than 30 flights were shown as cancelled on airport television screens.
Qatar Airways, in a statement on its website, said passengers holding a confirmed ticket to any of the four Arab nations between June 5 and July 6 are permitted to rebook their flights up to 30 days after their current departure date.
The airline said its offices would continue to operate as normal in affected countries.
Saudi Arabia's General Authority of Civil Aviation, however, revoked the airline's license on Tuesday and ordered its offices to be closed within 48 hours.