Competitors of Emirates, Qatar Airways and Etihad Airways have to dig deep into capacity statistics to find markets where the mighty Persian Gulf carriers are not succeeding. The good news is that there are some, but the bad news is that where it really counts, these airlines' growth rates are still frightening to the rest of the world.

An analysis of Persian Gulf carriers' capacity deployed over the past several years shows—not surprisingly—that they are adding huge numbers of seats in markets where they can obtain traffic rights (see graphs). On the flip side, governments in various parts of the world are still using restrictive bilateral air-service agreements as relatively effective tools to inhibit the Persian Gulf carriers' expansion, although countries with fast-growing markets—such as India and China—appear to have changed their strict policies.

A closer look into where the “Big Three” airlines are growing also shows that it is not only European and Southeast Asian carriers that have reason to worry about their long-haul margins, but also U.S. airlines. Emirates now has as many seats on these ultra-long-haul flights to the U.S. as it offers to Germany, which is obviously much closer.

There are only a handful of markets in which the Persian Gulf carriers' expansion plans are not working, shows an Aviation Week analysis of data provided by Innovata. Arguably, in many cases, that may be linked to the political situation in these countries rather than any flaw in the airlines' business models. Traffic has been stagnating or declining in markets such as Lebanon, Malta, Sudan, Uganda and Yemen, but all of these are very small.

The three most challenging markets for the Persian Gulf carriers are Turkey, Ethiopia and Canada. Emirates has halved capacity into Addis Ababa, Ethiopia, since 2009, Etihad does not fly there at all and Qatar has only just started to do so. Ethiopia is one of the few African countries that has a very strong flag carrier, Ethiopian Airlines, as does Kenya, with SkyTeam member Kenya Airways. Emirates' capacity growth has only been around 25% over the past four years—the airline had been achieving such figures typically in one year. Etihad has only just started flying to Kenya, but the market seems to work best for Qatar, which has doubled capacity over four years, albeit on what is still a modest level.

Turkey has also been a difficult market, although it is one of the region's largest economies and has a very large population with growing average disposable income. But Turkish Airlines has long posed a very strong threat to the Persian Gulf carriers' ambitions, particularly in Eastern Europe and Africa, and it has been very effective in protecting its home market.

Only Ethiopian and Turkish airlines seem to have shown much ability to cope with the competitive threat. For Canada, it is simply the lack of additional traffic rights being granted that protects Air Canada.

Other than that, there seems to be no stopping the Persian Gulf carriers' expansion. Emirates in 2014 is looking at another year of up to 20% capacity growth. And in spite of the fact that Dubai International Airport is likely to approach by 2016 the capacity ceiling predicted for 2020, there is some hope that Emirates can continue on its current path if a significant number of other airlines move to Dubai's new Al Maktoum International Airport.

Qatar Airways, the second-largest of the three Persian Gulf carriers, also has ambitious short-term goals. It plans to move to the new Hamad International Airport in the first quarter of 2014, once an extensive review of fire-protection measures is completed. Later in the year, Qatar will take delivery of its first of 10 Airbus A380s and first of 80 A350s. Etihad will also soon add two new types to its long-haul fleet, the Boeing 787-9 and A380, of which it has ordered 10 as well.

But as much as the three carriers appear to be in sync, there are still substantial strategic differences between them, which have only recently been unfolding. The strategy changes are based on the fact that Emirates, Qatar Airways and Etihad have all abandoned the idea of going it alone. They have become part of the world air transport system, rather than continuing to be seen as outsiders that other airlines feel the need to fight. The strategic differences mainly lie in how they are partnering with other carriers, instead of trying to operate independently.

Qatar Airways is the only one of the three that is now a member of one of the major global alliances, Oneworld. And one can see why its CEO, Akbar Al Baker, has made that choice. With a fleet of around 130 aircraft, Qatar is much smaller than Emirates, so it has an incentive to grow through partnerships and code-sharing. Also, global alliances tend to be effective in funneling additional traffic toward their members. Given that Qatar is such a tiny country, the airline needs passenger volume from other parts of the world. Around 80% of its traffic is only connecting through Doha.

Philosophically, it is also understandable why Etihad has decided to expand through acquisitions. With a fleet of 80 aircraft, Etihad is the smallest of the Big Three, and it is playing a game of catch-up. If the airline were only to grow organically, it would hardly be able to become as big as Qatar, let alone Emirates, but CEO James Hogan is convinced size and scale are needed.

The industry is divided about how Etihad is implementing that catch-up strategy, and the partners the airline has selected, including Air Berlin, Air Serbia (formerly JAT), Air Seychelles, Aer Lingus, Virgin Australia and, most recently, Jet Airways. Some of them—notably Air Berlin and Air Serbia—are incurring big losses. Air Berlin, in particular, would likely not still be flying without the various capital injections and rescue missions by its Abu Dhabi-based shareholder. Indian carrier Jet Airways, also in dire financial straits, promises at least to open up what could soon be one of the world's most lucrative air transport markets.

Hogan has made clear that he is not interested in buying a stake in Alitalia, but Etihad is understood to be in advanced talks with the Polish government about adding LOT Polish Airlines to its portfolio.

Etihad also has more than 40 bilateral agreements that do not include equity stakes. Most prominently, it code-shares with Air France, which has led to rumors about deeper cooperation plans.

Emirates continues to be uninterested in global multilateral alliances. Following its bad experience in investing in another airline (SriLankan Airlines), it is also no longer pursuing equity investments, although it was talking seriously with Air Berlin before Etihad stepped in.

But that does not mean Emirates is not partnering at all. On the contrary, its tie-up with Oneworld member Qantas has sent shock waves through the airline industry. The fact that Qantas gave up its long-standing joint venture with British Airways and moved its Asian transfer point to Dubai from Singapore led many to assume the end of global alliances is nearing. But now that the dust has settled, and despite the emergence of more previously unheard of tie-ups, it seems alliances are here to stay.

Qatar Airways' joining of Oneworld also has a lot to do with the group's more liberal approach toward members. Additional agreements outside the alliance are not only allowed but encouraged. And Oneworld is also accommodating the strong growth of Qatar, which in many transfer markets means growing at the expense of other members. “I have always said that alliances are the way to go,” Al Baker says. In his view, the other two alliances (SkyTeam and Star Alliance) “will be knocking on [Persian] Gulf carriers' doors.” But, to no one's surprise, Al Baker believes that “they have missed the best one.”