Just noticed that my wife's 2014 MBA 13" is not showing the battery status icon in the menu bar. When selecting the option in System Preferences, it disappears immediately. It also shows batter at 0% in System Preferences. In System Profiler, it shows no battery info at all. To check if it was an issue with the installation of the OS, I booted the High Sierra installer from USB, no battery icon shown, but the same USB on my MBP shows the battery icon. Tried with a Yosemite USB stick I had laying around, and the battery shows on both when booting from that. Only difference between the two are that the Air has an aftermarket battery, so obviously no support from Apple on this. Has anyone else seen this behaviour?