Israel has always considered using its military arsenal against anyone who sends rockets into Israeli airspace. What do you mean by aggressively defending your sovereignty? I think it is a new step in the escalating war between Hamas and Israel for Hamas to use anti-aircraft defense systems against INTRUSIVE foreign aircraft over Gazan airspace.
Islamist militants attack African Union base in southern Somalia (Reuters)
from the article: For first time, Palestinians in Gaza fire missile at IAF helicopter