A light on a crane would likely have been static or if it was operating have a very restricted field of moving and limited working hours and easily discounted as the cause. And of course the airport authorities would have been aware of construction in the vicinity.
I know some people have scoffed about the police drones but if they were legitimately used to try and track the other drones down the public could very well have reported those as drone spottings and of course the cycle then continues.