UFO Fuel

If UFO's are actually spacecraft from other civilizations, what kind of fuel do you they utilize?

I've heard some things about metallic hydrogen lately. I was thinking it would be an easily replenishable fuel, since hydrogen makes up 90% of the universe. If they have the technology to sustain it in a metallic state, which they presumably could if they have the technology for interstellar travel, it would be a convenient and powerful energy source. Also, I've read that metallic hydrogen is a superconductor and powerfully magnetic. Could that account for reports of UFOs interfering with different electronic equipment?

I believe in the prevalent theory of a super heavy, clean element like 115 that could be used to create artificial gravity fields for a craft to 'fall forward' into on a nearly limitless scale without waste and with minimal depletion.

I also think if we have recovered ANY element 115 THIS is the real reason that the existence of Aliens is kept from us. Not because of the Aliens, but because the Military/Industrial/Oil & Banking complex needs a consumer based addiction to fossil fuels for it's true power.

Just imagine if everything were suddenly 'free' and energy was abundant. THAT is the only concept that makes the powerful tremble.

I take my cue from Paul Hill, deceased NASA engineer who wrote on the subject of UFO mechanics. As he stated, I imagine they run on radioactive isotopes.