iOS Universal app seems slightly zoomed in on phon

I have an iPad app that I'm converting to a universal app to show on phones. It has both a tab bar and a navigation bar, and my problem is that they are both way too big on the phone. I could swear I heard Paul Hegarty (from the iTunes U class from Stanford on Swift app development) mention a switch or trick somewhere that would cause the bars to adapt to the iPhone, but I can't find it.

Here are screenshots of my apps bars, vs the Photos app in the iPhone 6 simulator to show what I'm talking about.

Not a huge difference, but significant on a small phone screen.

My fonts are also way to big, which is confusing since I have them set to the system "headline" or "body" options for all size classes, but that may be a separate issue.

Any help is greatly appreciated!

App written in Swift, using storyboards for iOS8, btw.

Edit:

The more I look at this, the more I'm convinced it's not related to the bars, but the entire app - the fonts and everything. The whole app appears to be zoomed in to 120%, which is subtle, but looks really bad and wastes space.

I have also now seen this in a second app - the Apple DateCell sample. It also appears 'zoomed in' when run on the iPhone 6 simulator.

Edit 2: This effect is even more exaggerated on the iPhone 6 Plus simulator - everything is even more 'zoomed in' looking - the top and bottom bars are almost twice the height they should be. This can be seen by downloading the Apple DateCell sample and running it.

Edit 3: ARGGGG, all this time wasted, and it was due to the launch screen image - why on earth would a launch screen image not being set cause the entire app to scale?

I finally figured this out - it was related to the launch screen image. Apparently if it's not setup right, the whole app scales on the iPhone 6 and 6 Plus for some reason. This question is what pointed me to the answer.

For me, I had to both create a LaunchScreen image in Assets, and set it in the project file, and ALSO select the launchScreen.xib as the Launch Screen File in the project. I don't have a real launch screen yet, so these are both just empty or defaults in my case.