Gulf carriers enter a new phase of growth, opposed by louder voices seeking to slow their expansion

But as the Gulf carriers grow, so the opposition from some European airlines and their governments is intensifying.

The accolades involve scale: Etihad is the largest 787-9 customer and Qatar the biggest for the A350. The sheer number of those and other aircraft on order concerns competitors. The potential challenge was exacerbated by Etihad's acquisition of Alitalia, which has provoked responses from many European airlines but also Delta, which has a JV with Alitalia and does not like Gulf carriers.

Gulf network carriers in the past had encountered significant protectionism in Europe and Australia. Some of those continue, notably in the bastions of protective air access (all of the Gulf airlines want more German access - where Turkish Airlines has already fallen out with Lufthansa because of its better market product - while Emirates wants to grow in Lyon) but antagonism in the US is also increasing, partly fuelled by pilot opposition.

It is this evolving aeropolitical atmosphere and securing route approvals that are arguably the greatest concern for the large incoming fleets. As of Dec-2014, according to CAPA's Fleet Database, Emirates has 284 aircraft on order, Etihad 213 and Qatar 215. Markets in North Asia and Africa in addition to Canada, Germany and India can be particularly protectionist. China stands out as the market with most longer term potential - but greatest restrictions. India too is essentially protective, although the Gulf carriers receive far greater access there than in China.

A liberal agreement or even open skies does not automatically mean relaxation of market access limits. Politics plays a part too. Both the UAE and Qatar have open skies agreements with the US, but some American airlines are seeking to restrict Gulf carrier access, following the trend in Europe. And, were it not for the higher political imperative of maintaining relations with their Middle East partners, Washington might well be swayed by the new defensiveness.

If Gulf carriers are still proceeding on their steep growth paths, some influential European airlines are still feeling threatened by Etihad's acquisition of Alitalia - adding to existing large stakes in airberlin and Etihad Regional.

European carriers are also wary of Etihad's stake in India's Jet Airways, which has prompted Etihad to receive greater access to that key market. With greater access, it is believed Etihad has been able to grow in the India-Europe market whereas previously its connections from India focused on North America. There are direct services between India and Europe by third and fourth freedom operators, but they mostly focus on Delhi and Mumbai, leaving the rest of India to a one-stop service at best.

Etihad's partnership strategy is bearing fruit; it received about a quarter of airline revenue from partners, for over USD1 billion in 2014. The Abu Dhabi carrier launched Etihad Airways Partners, which is to be marketed as a "brand", in some ways similar to the concept applied by the global alliances. Its initial Partners members are all carriers in which Etihad has equity, but neither part owned Aer Lingus nor Virgin Australia, are members of Partners. airberlin, a member of oneworld, is a member of Partners as the "brand" allows alliance members to join, but it is unclear if other alliances will permit this. The much tighter brand of Star for one, has said it is still evaluating the developments.

There will surely be further growth in members in 2015. For now, Partners accounts for 2.6% of global capacity (measured in available seat kilometres) whereas oneworld, SkyTeam and Star account for 18%-24%.

Emirates meanwhile continues its organic growth, relying to a far greater extent than any other airline on the attractive operational and customer features of the A380, while being the largest consumer of 777s. Despite detractors, it has undoubtedly become one of the most profitable airlines in the world, no matter its ownership. As it leads the Gulf charge into the US, it perhaps is the most conspicuous of the three. Undoubtedly it is not just the physical intrusion, but also the dramatic gulf between the inflight products of the US airlines and those of the new widebodies that causes concern that customers will quickly migrate to the Gulf airlines - it's not just the Gulf, it's also the gulf.

There is, however, little comparison between the impact on US airlines and hubs compared with Europe. Whereas the European majors and their favoured hub networks are directly threatened by the Gulf carriers (along with the "fourth" Gulf airline, Turkish Airways), by contrast the US airline route structures are largely complementary with the Gulf airlines.

For that reason, there is a real prospect that at least one US airline will strike up a strong partnership with a Gulf carrier in 2015.

Navigating the restrictionist debates is not straightforward. Gulf carriers may be united on certain matters, but the fact is, aside from geography, each is different. There is a growing divide between Emirates/Qatar and Etihad as their respective strategies evolve.

Air France protests the Gulf carriers but has also indicated it would favour a JV with Etihad - which has broader links with SkyTeam member airlines. IAG may also form a JV with Qatar Airways (which it sponsored into oneworld, the only one of the Gulf airlines to belong to a global alliance), but IAG and CEO Willie Walsh have long been supporters of Gulf carriers.

The "Middle East Big 3" rightfully attract attention - Emirates is already the world's largest international carrier - and they have massively disrupted the world's long-haul markets, just as the traditional network airlines were looking to long-haul as a refuge from the pressures of LCCs in their local markets.

But the Big 3 are not the sole story; the Middle East is home to a range of carriers. Emirates, Etihad and Qatar account for an impressive 38% of seats to, from or within Middle East. They are three of the four largest carriers in the region (second-largest is Saudia) with ambition and plans to capitalise on it. But outside these three, the opportunities and challenges are disparate.

Regionally focused carriers such as Gulf Air and Royal Jordanian help to fulfill the needs of intra-regional traffic, partly by choice, partly as a shelter from their more powerful long-haul neighbours. This regional segment has been severely hurt in recent years from factors including the Arab Spring.

Other flag carriers have not reached their potential. Oman Air may have new aircraft and a number of awards for its service, but the carrier lost USD291 million in 2013. This brief mention was overshadowed by the emphasis on the carrier's social and economic contribution nationally, which the airline calculated at more than USD1 billion. It has a point, but with plans to increase the share of low-yielding transfer traffic from 60% to 70% of passengers, the subsidy argument weakens. That may be beside the point: Oman has clearly committed to having a flag carrier, and it is far from the only government to hold this view. Yet in today's world, many less affluent countries are finding that it is just as effective to encourage foreign airlines to provide the service.

Other flag carriers are suffering from problems not all of their own making. Kuwait Airways has an old fleet it is only now starting to order replacement aircraft for, but its image will require some time to mend. Iran Air's old fleet is the result of sanctions that may be lifted (and if so, is sitting in an undeveloped market with enormous potential). Pakistan International still has a poor brand reputation and a difficult political environment at home. This creates opportunity for other carriers, be it the network giants or Kuwait's Jazeera Airways.

Jazeera originally aspired to a bigger role but has now settled into a more sustainable mould, with growing yields and profits from its flying, as well as sub-leasing aircraft to cover seasonal peaks and troughs. A new business plan is surprisingly modest. Others - Bahrain Air and RAK - did not get a second chance and have been relegated to history.

There are once again start-ups in the Middle East as Saudi Arabia seeks to grow domestic services. Despite having the biggest home market in the region, Saudi Arabia has been a reluctant participant in a new competitive world, but is gradually opening up its domestic market. Qatar Airways and a group linked to Gulf Air have been awarded the right to establish foreign-owned carriers - Al Maha and Saudi Gulf respectively - but the timeframe is unclear. It was only at the end of 2014 flynas was allowed to raise fares above a cap, but only under certain conditions. This was to help balance the immense value of dominant competitor Saudia receiving discounted fuel.

Saudia itself is also frustrated with government policies and from being forced to operate unprofitably. The carrier has spoken of ambitious long-haul growth, but this seems out of sync with Saudi's still-reserved atmosphere. Saudia has been undergoing privatisation and Kuwait Airways is expected to as well, but overall there are few publicly listed - or even non-government-owned - airlines in the region.

One exception is flynas, which attracted negative interest in 2014 for abandoning its long-haul strategy, which management found too problematic mere months after launch. It is now honing its strength domestically and regionally with a hybrid product.

The Middle East traveller likes pampering and even demands it - or that is the conclusion of the region's LCCs. Jazeera was an early carrier to "hybridise", adopting characteristics typically associated with full service carriers. Jazeera offers a near unprecedented 40kg checked luggage in economy while flydubai has introduced business class lounges and is constructing a premium lounge at Dubai.

The ability of LCCs to move up-market means they start to encroach on full service carriers. Dubai owned and based LCC flydubai overlaps with Emirates on numerous destinations, but the bigger airlines have scale and, in any event, are often more focused on connecting traffic, especially long-haul.

The main non-government owned LCC in the UAE, Air Arabia, is successfully continuing with a more basic model and, despite regional turbulence - notably in Egypt - the independent operator has been versatile and proven it is a survivor. LCCs account for only 16% of seats within the Middle East compared to 40% within Western Europe or 58% within Southeast Asia. Still, that LCC share in the Middle East is up from 8% in 2009.

The focus on Middle East aviation will remain in the full service spectrum, but this is wide and varied. Unlike most other markets in the region, the UAE's airline industry is relatively transparent, due to its numerous carriers, business models, hub status, and size - especially in the case of Emirates. The UAE will continue to benefit from its sound strategy, and show an example for others to follow.

The overall outlook for the Middle East is bright - but it is not without its own internal challenges. Dubai International Airport needs to address growth constraints until Emirates is ready to move to the massive Dubai World site next decade. Further, air traffic is congested, caused by fragmentation and extensive closed airspace. Oil price volatility wreaks havoc on an industry with single-digit margins.

But the central risk for the expansion of the Gulf airlines in 2015 is external, as the collective of protective voices gains greater traction in Europe. Over time this will perhaps be muted by partnership evolution, but for the coming year this will be a major battlefront for the Big 3 - and, by association and scale, for Turkish Airlines.