The presidents of which two countries were killed in a mysterious plane crash?

The Presidents of both Rwanda and Burundi

Explanation:

On the 6th of April 1994, precisely in the evening  the airplane that was carrying  the Burundian president Cyprien Ntaryamira and Rwandan president Juvénal Habyarimana, of which they were Hutu, was shot down with a  surface-to-air missiles as it was ready to land in Rwanda, kigala.

The assassination of the two presidents initiated the way of the bloodiest events of the late 20th century which were The First Congo War and Rwandan genocide

nope.

explanation:

congress also has implied powers, which derive from the necessary and proper clause of the constitution and permit congress "to make all laws which shall be necessary and proper for carrying into execution the foregoing powers, and all other powers vested by this constitution in the government of the united states.