Neither are the Sukhois nor the Ospreys fast enough nor do they have long enough legs to be the xcom craft. The xcom aircraft have performance and capabilities almost as if they were ripped out of the pages of some 1960s popular mechanics magazine. I think the closest thing to the interceptor up there would be like some twin engined yak-141 type aircraft, with the pulse wave detonation engines that are theorized to power the mythical senior citizen 'aurora' aircraft. As for the plasma stealth, that's been floating around the internet for quite some time. A paper was first published about it in the 1950s. Then again, plans for flying saucers were found in post war germany, and Avro Canada tried to make a flying saucer like aircraft in the 50s and nothing came of it. Further, different aerospace companies at different times have tried to make plasma stealth work and despite 50 years of technical advancement, there is still nothing. I severely doubt that plasma stealth is about to break out in a big way.