With the lone exception of TWA-800 /sarc, large commercial airliners do not spontaneously break apart leaving no time for a distress call.
a MANPAD cannot cause such damage. A large SAM, or bomb aboard the plane could. I generally doubt terrorists in the Sinai have large SAMs, although a rogue Egyptian army unit could.
Lots of advanced AA units mostly of Russian origin were looted during Hillary’s War and found their way - according to numerous reports - into the Sinai and beyond.
Were these only manpads or did Libya have high altitude SAMs? In Reagan’s time they did, so it is safe to assume that Qaddafi still had Russian SAMs which would be able to shoot down airliners.