I have considered the possibility of it being a contrail or something happening within the optics of the telescope. I don't think a contrail will appear beside the disk of the sun when viewed through a solar filter. A contrail would darken or distort the light, along an airplanes path, when in front of the solar disk.
If a spec of dust or insect happened to get into the optics of the telescope, it would simply serve to darken the intensity as opposed to show up as a concentrated source of light. Plus it moves quite uniformly.
The timing seems consistent with a meteor going through the atmosphere. There is a lot of atmospheric volume for the meteor to pass through since the video was taken near sunset. This, combined with it possibly being a perspective view of the meteor trajectory. It was viewable for about 2 to 3 seconds which may be possible. Its trajectory seems to be in the right direction. I would think it is much more likely to be going downward with respect to the horizon than upwards. Once you flip and reverse the image, the trajectory goes down and toward the left.
I also contacted an expert in solar viewing to make sure I wasn't too far off the mark in intepreting the phenomenon. Phil Goode, of the Big Bear Solar Observatory, indicates it looks like a terrestrial meteor. I would be surprised if this is the first daytime meteor streak recorded in video while viewing through a solar filter. But I haven't found any mention of such on the web. But it can probably make the claim of being the first daytime meteor streak viewed through a solar filter while Venus is transiting the Sun.
As for the UFO angle, it wouldn't surprise me if people start talking about it in this way. But this is sensationalizing the observation and its interpretation. One should rule out the much more likely interpretation, in my opinion, of it being a meteor before jumping to the UFO conclusion. As Richard Feynman once remarked when asked if UFOs exist, he stated that they are highly unlikely, but one cannot prove they don't exist. One can see his discussion on YouTube at
http://www.youtube.com/watch?v=wLaRXYai19A. And it may be difficult to distinguish this meteor from space junk or an artificial satellite re-entering the atmosphere.
It would be really interesting if someone else caught the meteor streak on video. Then one could compare the timing and trajectory in connection with the viewing location.