Major Gulf hubs, including the world's busiest international airport Dubai - which normally handles over 1000 flights a day - remained closed for a fourth day on Tuesday, slashing capacity on popular routes such as Australia to Europe, where Emirates and Qatar Airways normally have a high market share.
Australia's Flight Centre Travel Group has experienced a 75 per cent increase in calls to its stores and emergency assistance lines since the crisis began and has teams working around the clock to help disrupted customers, its global managing director Andrew Stark said.
"Australians are very resilient and are already rebooking flights to the UK/Europe via alternative routes via China, Singapore, and other Asian hubs, as well as North America via hubs such as Houston," he said.
Carriers that offer non-stop Asia-Europe flights are able to bypass the closed Middle Eastern airspace by flying north via the Caucasus then Afghanistan or south via Egypt then Saudi then Oman.
But it may add to flight times and fuel usage, driving up costs at a time when oil prices have spiked, in a move that could lead to higher fares over the longer term.
"Right now the whole of the Middle East is out of bounds, which is a high price for some airlines," said Subhas Menon, head of the Association of Asia Pacific Airlines.
"If then Europe can only be served at a high cost, airline profitability will be undermined. At the end of the day, the price to pay is connectivity."
Alton Aviation Consultancy said airlines operating non-stop services or through alternate hubs outside the affected region - including Hong Kong's Cathay Pacific Airways, Singapore Airlines and Turkish Airlines - may see short-term gains as passengers shift away from Gulf-based carriers.
Reuters' checks of several airlines' websites on Tuesday showed few near-term bookings available and high prices on offer for flights from Asia to London.
Cathay Pacific's website showed no available economy-class seats on the Hong Kong-London route until March 11, with a one-way ticket on that day costing at least HK$21,158 ($A3,816), falling to a more normal HK$5,054 later in the month.
For flights from Sydney to London, Qantas Airways is not offering any economy-class tickets on flights via its normal Perth and Singapore routings until March 17, when one is available for $A3,129 ($US2,220) one-way.
For earlier dates, it has pricey options with non-traditional stopovers such as Los Angeles and Johannesburg.
Thai Airways is experiencing fully booked Europe-bound flights as European tourists opt for direct routes rather than transiting through the Middle East, according to Thailand's Transport Minister Phiphat Ratchakitprakarn.
A search of the Thai Airways site for travel from Bangkok to London showed tickets were sold out until late next week, and then fares were high.
Taiwan's EVA Airways said bookings for its Europe-bound flights had surged as Asian and European passengers seek alternative routing options.
