Somehow the simulator had no iPad devices listed. Only the iPad device itself was available. To get the devices back you need to control-click on XCode and navigate to the following path:
- Open iOS Simulator is atÂ
/Applications/Xcode.app/Contents/Developer/Applications/iOS\ Simulator.app. - Go to Hardware > Devices > Manage Devices
Then you can add the iPad 2, iPad Air etc… back.