I still think it broke apart in midair because of a crack in the tail and an incomplete repair. Same thing happened to a Chinese plan recently. New airplanes are made of composite parts and there is almost no what a crack can be detected if it is internal to the composite material the way you can with metal/aluminum parts.
Downing Street believes “an explosive device” may have caused the plane crash in Egypt http://trib.al/KXhrq7K
I think the U.K. knows more than they are making public...
Breaking (YNet): UK suspends Sinai flights, says Russian jet may have been brought down by explosive device.