With the 787 Dreamliner, Boeing has managed to build an extremely fuel efficient plane for long-haul flights. But there's another, much smaller, feature of the aircraft that's causing some issues — the windows. Japanese airline All Nippon Airways claims that the windows, which can be dimmed electronically, simply don't get dark enough. "For our passengers to have good sleep, we realized that it is important to offer appropriate darkness during flights especially for long haul," spokesman Ryosei Nomura told Reuters.

The airline will reportedly be installing blinds in order to make lengthy flights more comfortable, and has requested that Boeing come up with a solution for the issue. However, there's no word on whether or not Boeing will attempt a fix of its own, as the company says that the response to the dimming windows has been "very favorable." All Nippon Airways currently operates seven 787s, and aside from the one issue the airline is reportedly happy with the aircraft — which is good news for Boeing, as the company has already taken more than 850 orders for the Dreamliner.