This proves that Apple will make it easy to handle it with one hand: iPhone 6 vs Samsung Galaxy S5: the two in a size comparison

macitynet.it:

The new iPhone 6 promises to be not only thinner but also more easy to hold and use than the Samsung Galaxy S5. This is what you can see from the new pictures. Thus confirming the design we've seen in the past few days, the iPhone 6 seems slightly smaller than the Galaxy S5 (which measures 142 x 72.5 mm), that further is a confirmation of the size of 4.7-inch display, as the Samsung Galaxy S5 in question is equipped with a display of 5.1 inches. Unlike the South Korean company's smartphone, however, the new iPhone 6 will be a lot thinner and have rounded edges, which allows to get your hand around the smaller device even if has a larger display.

This size comparison between the Samsung Galaxy S5 and the iPhone 6, says it all, Apple will design the iPhone 6 / iPhone Air so that it still will feel very comfortable in your hand, and it will still be very easy to handle with one hand (thank you Apple). The thinness and rounded corners is specifically made for that purpose. As usual, Apple would never release a product that doesn't have the best user experience possible. I'm sure it will feel great to handle this phone.