A couple of things to note here:
1) Ground workers can be certified to move airplanes on their own power, such as from a terminal to a hangar. Getting to that step is 90% of what you need to know to take off. Add a few flying lessons in a Cessna and you’re in the air.
2) Large airplanes don’t have ‘ignition keys’, or, I guess now, FOBs. Anyone who gets in can fly away to the friendly skies, providing the airplane is serviced to do so.
I suspect there will be a SERIOUS investigation over this and probably some added security measures (resulting in added costs to fly, obviously).
Not long after WWII a friends father and his buddy purchased a cheap Army surplus Stearman.
The pilot delivering it said that for a few dollars and a ride to the nearest train station he would give them a flying lesson.
After the lesson, they took it for a ride!
He said, take off was OK, flying around was fun!
The landing was a different story.
After multiple attempts, with many problems...
They went for it!
He said they bounced so hard he thought they had crashed, but it rolled on!
NEVER TOUCHED IT AGAIN and sold it for a loss.
Like it never dawned on the overpaid security kakistocrats that something like this could happen.