What happens next
What happens next will shed a lot of light on who was doing this. If they're never seen again then we'll probably never find out. If they wait until the military and the police have left then start flying again at Gatwick then it's probably personal and somehow linked to Gatwick specifically. If it's environmental protesters or someone who wants to cause maximum disruption then they'll do the same at Stanstead tomorrow, then Luton just after Christmas and Heathrow over New Year.
Whoever it is doing this has demonstrated a degree of planning and operational security awareness, so I doubt it's over.