Just to be clear sorry paint over flight surfaces is not something anyone flying can just ignore.

It is very able to bring down an aircraft if the wronge surfaces are stuck due to such paint. And most modern aircraft surfaces do not allow huge movement spaces. (Excepting some limited early stealth models that needed to grow at speed. But materials tech has hugely changed since early 60 when early stealth aircraft leaked fuel at take off)

Is it terrorism likely not. I at least cannot make an argument where tempory lack of 2 aircraft is a threat of terror.

But it is damage to the aircraft that requires funding to correct before use.