Sometimes with my iPhone 6 Plus when I'm shopping for flights in the flight option screeen the entire app will freeze. I have to completely close out of the app and restart over again. I close out my background apps often and the iPhone 6s Plus has 2GB of RAM so this shouldn't be a problem and only happens with the DL App. It also doesn't preform well with slow Wi-Fi as at MCO the wifi is painfully slow and the DL app will often kick me out of my log in and won't load my info when I put it back in and a error message pops up instantly. I always have to turn off my phones wifi when I'm there but I never have time to go and have it not automatically connect me to MCO Wi-Fi.