How mobile-friendly is Delta Airlines?
The iOS apps from Delta Airlines will work with all of your Apple devices, from iPad to iPhone
For Delta Airlines SkyMiles members, you'll be able to manage your account from the app, though using their website will no doubt provide more functionality
The Android apps from Delta Airlines work with all Android phones and tablets from various manufacturers (Samsung, LG, Google, etc.), and Android Wear watches might also be compatible. As is often the case, the Android app offers the same functionality as the iOS app.
Also take a look at Delta Airlines's website by clicking here — you should be able to do what you need there.