The world's fastest-growing airlines suddenly aren't anymore

When a video of a passenger being dragged off a United flight went viral last month, the U.S. carrier's Middle Eastern rivals were quick to mock its customer service. Qatar Airways updated its smartphone app to say it "doesn't support drag and drop."

The ribbing was justified. Over a decade of expansion, Qatar Airways, along with Emirates of Dubai, the world's largest airline by international passenger miles traveled, and Etihad Airways of Abu Dhabi, wowed customers with superior service and better-value fares. Over the past decade the big three Gulf carriers and Turkish Airlines tripled their passenger numbers, to 155 million in 2015.

They went a long way to dominating long-haul routes between Europe and Asia. Most international airlines rely on travelers going from or to their home countries, but customers of the four "super-connectors," as they are known, mostly just change planes at the carriers' hub airports en route to somewhere else.

A slowing of this spectacular growth was at some point inevitable. But it has been exacerbated by several things.

First, the airlines have been deeply affected by the halving of the oil price since 2014, which has reduced their customers' spending power and sharply cut demand for air travel from the Middle East itself. In particular, energy companies, responsible for 29 percent of GDP in the Gulf states, are slashing travel in business class, the most profitable cabin in airlines' fleets.

Second, geography has turned sharply against them. When Sir Tim Clark, president of Emirates, helped Dubai's government to set up the airline in 1985, he was quick to spot that a third of the world's population lives within four hours' flight of Dubai, and two-thirds within eight.

"They were in the right place at the right time," said Andrew Charlton of Aviation Advocacy, a consultancy. "But now they've been caught in the wrong place at the wrong time."

The third, and latest, blow has been a set of travel restrictions introduced by the Trump administration. Since January, Trump has made efforts to ban the citizens of several Middle Eastern countries from entering the United States. Despite various legal challenges, those efforts have hit inbound traffic. In March, the U.S. also banned electronic devices larger than a smartphone, chiefly laptops, from the cabins of planes flying between eight Middle Eastern countries and its own airports (Britain also introduced similar restrictions). The issuance of U.S. entry visas has been cut and security vetting increased.

After the first travel ban, demand fell by 35 percent on Emirates' American routes. The banning of laptops has had an even worse effect on the Gulf carriers. The airlines have started lending their own devices to business-class passengers, but demand is still tumbling.

Emirates said on May 11 that airline profits fell by 82 percent in the past year. Results for Etihad, expected this month, are likely to make grimmer reading. In March Turkish revealed its first annual loss since its privatization in 2004. Qatar, meanwhile, is still growing, partly because the government is able to support it. Its alliance with IAG, owner of British Airways, in which Qatar has a 20 percent stake, also means that it is still seeing increases in passengers originating from London and then flying on to Asian countries.

Etihad is worst-placed. It has pushed out its CEO, James Hogan, and is in the midst of a strategy overhaul. Its move to invest in European airlines, including Italy's national carrier, Alitalia, and Germany's Air Berlin, has been disastrous.

It is possible that the commercial pressure may ease. Yet the breakneck growth of the recent past is unlikely to resume. Two new aircraft — the Boeing 787 and the Airbus A350 — make it profitable to carry smaller numbers of passengers over long-haul routes. Secondary cities half a world away from each other can increasingly sustain direct connections. That eliminates the need to change planes in the Middle East.