There's an interesting question I heard once: When a drone pilot is done with his shift and goes home, is he still a combatant?
Let's see what the
Red Cross thinks.
Rule 3. Definition of Combatants
Rule 3. All members of the armed forces of a party to the conflict are combatants, except medical and religious personnel.
Alright then. Being part of the armed forces of a nation at war automatically qualifies you as a combatant, period. Wikipedia tells me the same rule is true (but also more expansive) for treatment as a POW. I can't imagine it would ever be a particularly relevant question. I suppose it could happen that the drones are being run by a civilian agency, or espionage (such as the CIA) or something. Then I suppose they could be held as civilians and charged with murder, but again this really only applies to POWs, and I can't imagine many scenarios with POW drone operators. Maybe you mean combatant in the sense of "are they legitimate targets". In that sense, I think the answer is that they are, but I still doubt bombing their houses or something would be looked favorably upon by a military tribunal. I do not recommend trying it, in any case.
As for terrorism, Wikipedia informs me there are two forms of combatants: privileged or unprivileged. Privileged means "in some way, shape, or form, is/was part of a regular armed force or organization similar in design and function to a regular armed force", and "did not violate certain rules while so" (those being not pretending to be a civilian, etc), and exempts you from trial under civilian law. Unprivileged means a combatant who isn't both of those things; while an unlawful combatant still must be treated humanely, it also means they can be tried for their actions, based solely on my reading here. Incidentally, it is impossible to be a lawful combatant in a conflict not involving two nation-states, so based on everything here, I would say that Jordan was within it's legal rights to try, convict, and sentence the two to death.