Nato assistance to the Baltic countries . it's nothing new!
The four Danish F-16 fighters are not in Estonia because of this incident! They are there because of a Nato air policing agreement to patrol the air space of the three Baltic member states! Estonia, Latvia and Lithuania have no airforces of their own and it's nothing new! Likewise British Typhoons have recently been deployed to Lithuania.
However it goes without saying that the Baltic nerves are a bit raw in the present political climate and the Air Policing agreement might trigger the odd excursion the other way round!