Yes, but theoretically shouldn't do any damage as the aircraft is itself 'floating' and not connected to a 0v 'Ground'. The engines, chassis and all metal surfaces are bonded together along with busses to provide a local electrical return path. Composites (such as Carbon Fibres) usually (though not always) have an integral mesh or carrier strip which is bonded to the vehicle 'ground'. In flight it could be quite common for an aircraft to be charged at quite a high potential - so it's 'ground' is not at 0v, but some arbitrary 'floating' (pun intended) value.

You could connect a PICs Vdd to several hundred kV (and happilly run it) - providing Vss is never more than say five volts lower than Vdd... I have an application for a domestic boiler Gas Ignition board using a PIC where Vdd is actially 0v (Ground) and Vss is -5v (it's easier then to use Comparators to detect if you have a flame as it creates negative ions). You can mess things around quite happilly providing you stay overall within the Datasheet parameters.