One of the most talked about product launches of 2014 is the iPhone 6, but rumour has it that Apple is actually working on two new iPhones for this year with different sized screens. The iPhone 6 is expected to have a 4.7in screen, but there's also talk of an even bigger iPhone dubbed the iPhone Air or iPhone 6L with a 5.5in screen.

Here, we've gathered the evidence to bring you everything we know about Apple's bigger iPhone, also sometimes referred to as the iPhablet, as well as some concept images and leaked parts as we get them.

If you're looking for information about the 4.7in iPhone, visit our iPhone 6 rumour round-up article.

A bigger iPhone has been hot topic for a while now, especially as bigger smartphones with larger screen sizes have grown in popularity. The iPhone is one of the smallest high-end smartphones now available, with some 'mini' or 'compact' versions of popular smartphones even sporting bigger screen sizes than Apple's iPhone 5s and iPhone 5c.

There is also a growing trend for 'phablet' devices, which fall between a smartphone and a tablet. They range in size, but are usually around 6in, with Samsung's Galaxy Mega actually boasting a whopping 6.3in display.

In addition to a bigger 4.7in iPhone 6, there's talk of a 5.5in Apple phablet device, which we're talking about in this article.

Not everyone's keen on the idea of a bigger iPhone, however, and many argue that the 4in display that can be controlled with just one hand is a huge selling point for the iPhone. But it has become clear that bigger iPhones are growing in popularity so we'd be surprised if Apple didn't launch an answer to that trend soon. We're slightly dubious about the idea that Apple will go to the extreme of 5.5in for its iPhone, but the rumours are mounting so its beginning to become difficult not to believe them.

Here, we've rounded up all of the speculation, images and rumours about the bigger iPhone, which has recently been dubbed iPhone Air, and discuss the question of whether the bigger iPhone will be Apple's next flagship or a whole new launch to expand the iPhone line-up.

We won't know for sure until we hear confirmation from Apple itself, but for now, we can weigh up the evidence to give us some clues as to what a bigger iPhone might be like. Apple hasn't kept completely quiet about a bigger iPhone, though. Read on to find out what the company's executives have been saying.

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What Apple has said about a bigger iPhone

Apple CEO Tim Cook hasn't ruled out the possibility of a bigger iPhone. In April 2013, during Apple's quarterly earnings call at the time, Cook said: "My view continues to be that the iPhone 5 has the absolute best display in the industry. We always strive to create the very best display for our customers."

"Some customers value large screen size, others value also other factors such as resolution, colour quality, white balance, brightness, reflectivity, screen longevity, power consumption, portability, compatible apps, many things," Cook continued.

"Our competitors have made some significant trade-offs in many of these areas in order to ship a larger display," Cook said. "We would not ship a larger-display iPhone while these trade-offs exist."

During the D11 conference the following month, Cook repeated his thoughts about a bigger iPhone. "A large screen today comes with a lot of trade-offs," he said. "Customers are clearly looking at size, but they also look at things like: 'Do the photos show the proper colour?' the white balance, the reflectivity, battery life, brightness, the longevity of the display. There are a whole bunch of things that are very important."

It's likely that Apple is hard at work trying to banish those trade-offs in order to launch a top-quality iPhone with a bigger display at some point. After all, it has been almost a year since Cook said those things.

Since then, Cook has dropped a few hints about the future of the iPhone, and some of those suggest the future is indeed bigger.

In December, Cook wrote that Apple has "big plans" for 2014, which we think could be a sneaky hint at a bigger iPhone.

Cook has also said that he believes there are significant opportunities for Apple to expand the position of products such as the iPhone, and had noted that his statement that Apple doesn't aim to make the most smartphones has been misunderstood, again hinting that an all-new iPhone could be on its way to join the iFamily.

Further evidence from Tim Cook that suggests we're going to see a bigger iPhone this year comes in the form of a puzzling comment from the Apple CEO. When talking about his promise to introduce products in new categories, Cook said that any "reasonable" person would consider what's on the cards as a venture into a new category. If Cook was talking about an iWatch or Apple television, it's unlikely he would have felt the need to specify that not everyone will consider the new product part of a new category, which hints that it may in fact be a bigger version of Apple's iPhone.

Bigger iPhone rumours: What the analysts & Apple watchers say

There's a long list of analysts and Apple watchers who claim there will be a 4.7in and 5.5in iPhone this year. The analysts include well-respected and regularly accurate KGI Securities analyst Ming-Chi Kuo, as well as UBS analyst Steve Milunovich, Piper Jaffray analyst Gene Munster, DisplaySearch analyst David Hsieh, KDB Daewoo Securities and Cantor Fitzgerald analyst Brian White.

Plus, reports from Japanese publication Nikkei, Reuters, The Wall Street Journal and Commercial Times have also reiterated the 4.7in and 5.5in iPhone 6 rumours.

Bigger iPhone rumours: iPhone Air

In July, rumours emerged from China suggesting that Apple is planning to name its 5.5in iPhone the iPhone Air, which would join the iPad Air and the MacBook Air in the Air-branded line-up. There has been talk of an 'iPhone Air' for a while now, and it would make sense. After all, it's the bigger iPad that's called the iPad Air, so perhaps the bigger iPhone will adopt the same name. We think Apple will want to diffrenciate the iPhone 6 and bigger iPhone significantly, so naming it the iPhone Air could be just the way to do so.

Bigger iPhone rumours: iPhone 6L

In August, new reports from Apple Daily showed new photographs of allegedly leaked display panels destined for the 5.5in iPhone, which the report claims could actually be called the iPhone 6L. While we can't confirm that the iPhone 6L rumour is true, it's certainly possible, and almost makes more sense than iPhone Air for the bigger device.

Should Apple release a bigger iPhone?

Barclays Capital analyst Ben Reitzes has said that Apple needs to launch a bigger iPhone because he expects the larger phone market to dominate smartphone shipment growth into 2015.

When Apple launched the iPhone 5 with a bigger display, Apple explained that the reason for increasing only the iPhone's height and giving the iPhone a 4in display was to ensure that it could be used with one hand. Reitzes says that the one-handed use of the iPhone will be "less important since phone calls are becoming less important than navigation, texting, videos, books and web access for many."

The consensus around the web seems to conclude that Apple is unlikely to get rid of a 4in iPhone option. Here at Macworld, we'd like to see Apple release two new iPhones this year, a new flagship smartphone that is a successor to the iPhone 5s and likely called iPhone 6, as well as a bigger option for those who want an iPhone with a larger display. It's been suggested, though, that Apple will continue to sell the iPhone 5s as its 4in option, adding a 4.7in and 5.5in option to its line-up as the new iPhones for 2014.

The launch of the iPhone 5c, and also the iPad mini, proved that Apple is no longer adverse to introducing more than one size of device in each line-up, so we think Apple would be wise to keep both a smaller and larger version of the iPhone to avoid upsetting fans of the smaller form factor.

Bigger iPhone release date: When is the iPhone Air coming out?

We're expecting the 5.5in iPhone to arrive later this year, either during an iPhone 6/iWatch launch event, at an iPad event or at its own, separate event.

Taiwan's Economic Daily News has suggested that Apple will launch the 4.7in iPhone 6 in August, followed by a bigger, 5.5in model in September, according to sources from the supply chain.

We think it's unlikely that Apple will launch two new iPhones within such a short period of time, unless it decides to unveil both iPhones at an August event with the first, smaller model becoming available to buy sooner than the 5.5in model, which would go on sale slightly later.

Apple retail stores have reportedly begun blacking out holiday dates for employees in September so we're certainly expecting an iPhone event then, but whether both iPhones will launch then is less certain.

More specifically, rumours suggest that 19 September is the date to mark in your diaries.

However, according to GforGames, a post on Weibo suggests that the iPhone Air and iWatch will be released together in December, much later than previously expected.

Respected KGI Securities analyst Ming-Chi Kuo has also suggested that there is a delay, claiming that its release date might be pushed right back to 2015. The delay is apparently to do with the in-cell touch panel used in the new device, and also colour unevenness seen on the iPhone Air's metal casing.

Bigger iPhone rumours: Screen resolution

Not much has been said about the 5.5in iPhone in terms of specs, but one thing that has been talked about a bit is the screen resolution.

DisplaySearch analyst David Hsieh has published a report to suggest that the 5.5in iPhone will have a high pixel density of 401ppi, compared with the iPhone 5S's 326ppi.

KDB Daewoo Securities has shared some alleged resolution specifications of the bigger iPhone, too. It claims the smaller of the two rumoured devices will have a 1,920 by 1,080 pixel display (468ppi) while the phablet will have a 2,272 by 1,280 pixel display (474.14ppi). By comparison, the iPhone 5s has a pixel density of 326ppi.

There is also talk of quantum dot technology being used in the bigger iPhone, which would improve colour accuracy of the display – one of the trade-offs Cook mentioned.

Bigger iPhone rumours: Sapphire display & Liquidmetal

In order to achieve a bigger iPhone, Apple may use sapphire for the glass screen, liquidmetal for the chassis and thinner bezels to keep the overall size of the device to a minimum.

Apple's Sapphire plant in Arizona could be used to manufacture 200 million 5in iPhone displays per year, according to reports that emerged in February. Recently published documents revealed that Apple and manufacturing partner GT Advanced Technologies are aiming to open the new plant in Arizona this month, and Apple CEO Tim Cook has confirmed that the plant is indeed for sapphire glass, as previously rumoured.

Sapphire glass is more durable than Gorilla Glass, so could be an ideal material to use for the bigger display.

There has been some doubt cast over the use of sapphire glass in the iPhone Air, though. In July, the Telegraph published a report that suggested that the sapphire material isn't being used for the iPhone Air because of "disappointingly low yield rates."

Liquidmetal is also said to be more durable than aluminium, and therefore can be used in smaller quantities to be as strong as the metal used for Apple's current iPhones. This would enable Apple to keep the bigger iPhone light and thin, despite the bigger screen.

Plus, removing the bezels in the bigger iPhone to create an edge-to-edge display would mean Apple could introduce a bigger display without the need to increase the overall size of the iPhone too much.

Bigger iPhone leaked images: What will the iPhone Air look like?

There haven't been many leaked images of the 5.5in iPhone, but there have been numerous for the 4.7in iPhone, many of which you can see here.

We do rather like this photograph of both the 4.7in iPhone 6 and 5.5in iPhone Air side-by-side (below). They're just mockups, but they're very convincing ones, and we can imagine Apple launching devices that look like these ones. These photos came from previously accurate blogger Sonny Dickson on Twitter.

There's also a video that appears to show the same mockups as Sonny Dickson's, but this time they're being compared with the iPhone 5S. Take a look:

Concept images of the bigger iPhone have also emerged, including the image at the top of this article created by Nikola Cirkovic.

A new concept spotted on ConceptsiPhone and created by Joseph Farahi includes several well-rendered images and a video that shows a 5.1in iPhone 6. It's thinner, has a higher-resolution display, and also has solar charging capabilities.

In July, Chinese repair firm GeekBar shared photos of what is believed to be the logic board of the iPhone Air, as shown below. 

 

We've also seen an alleged volume/power flex cable and SIM card tray destined for the iPhone Air, via Apple.club.tw.

We'll bring you more information and images of the 5.5in iPhone Air as they emerged, so check back regularly.