No, it is not a 'serious' offence demanding payback. It happens all the time between nations. WW3 would have started a long time ago if civilized nations starte

No, it is not a 'serious' offence demanding payback. It happens all the time between nations. WW3 would have started a long time ago if civilized nations started shooting down each others aircraft that inadvertently or deliberately crossed borders for short periods. Besides Turkish aircraft violate Greek air space all the time - so it extra-ordinarily hypocritical of them to state that they are guarding their sovereignty. Turkey had deliberately planned this operation with the F16's in the air and even a media team ready to capture the 'action'. The only reason Turkey does this is because they are a member of NATO. If they weren't, Erdogan wouldn't have the guts to go anywhere near the Russians. Though the Obama administration officially supports Turkey, I don't think the NATO brass is happy about this. Chinese aircraft violate Indian air space on a regular basis. Our fighter aircraft just gently escort them back, record the violation and sends the same to their designated military contact. It doesn't even make the official news. No civilized air force shoots down another air force's jets for minor border violations. Ask any air force officer.