So watching that footage of the plane disappear makes me think that, while seemingly legit, I could see that being a military exercise with the planned result: The downing of a jet aircraft. To live test a system like that, you need an actual (defenseless) plane at actual altitude that doesn't want to be shot down. Military is out for obvious reasons. Even the airline (Malaysian) and nationalities (not a military, nuclear or economic power) or work from an international incident perspective. Seriously how long was that in the news? A month?
My conspiracy brain would have me believe that was the footage from the exercise. Three angles of a 777 over the ocean? One from a spy satellite, one is thermal, and another a high altitude spy drone? That's a lot of expensive eyes on the ocean.
So either we knew about the aliens (who traveled millions and millions of light years) attacking a plane and deployed equipment to gather intelligence for defense purposes (we won't be able to repel firepower of that magnitude)
Or a successful test of an awful weapon system with the end of the tape doctored (post explosion) to blame it on aliens and never actually have to answer for it.