Lyric discussion by mrnice 

The pre-OK Computer period is known for excessive touring and the band's tiredness of it. Just imagine flying around to all the biggest cities of the world, mostly seeing airports and venues. The aircraft is what transports him 1000 feet/second. The part about the sparks is Thom's way of saying that there is too much energy, both for him personally and for the world. Too much energy used in a short amount of time. It would be reasonable to relax and save some of it for later. The title means he never feels at home and that the thing barking at him evokes a association to him being a ghost - he is lost from the world and unsure that he will ever get back from the state of tourist to a settled person (and if he never goes back to settled person, then he is like a ghost to those settled. Dogs always belong somewhere and probably the most settled animal in the world)

The sparks a-flowing goes with the spiritual feel of the album (karma, reincarnation etc) and suggests that the narrator has an aura that the animal can see.

I think Thom took his personal themes at that moment and converted it into something mystical, mythical and general.

Lol, of course the aircraft doesn't fly 1000 feet/second. Maybe he exaggerates to express how insanely rushed it feels like. The many sci-fi aspects of the album also allows for such exaggeration to fit in naturally.

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