Very interesting and spectacular video.
That being said what could be done concretely from a fighter ? I can imagine the very improbable case of the airliner being still flyable but having lost all NAV and COM. Extremely unlikely but ok... Past that there is the hijacking scenario. Assuming a positive identification of the situation can we seriously envision shooting down a fully loaded passenger aircraft over continental Europe? Given the probable time frame can we immagine, say, the Italian airforce shooting down an aircraft over Austria with the plane actually crashing in Hungary (just as an exemple to underline the massive mesh of overlaping sovereign airspaces)? I really hope we'll never have to find out...