Stars, a plane, and something else.

I took this picture one night a week ago. It's a thirty-second
exposure of the sky, thirty seconds because, even though I knew I
would get star movement, it's the easy long-shutter-speed to choose
with the Fuji X100 camera.

It is looking at the SW sky a couple of hours after sunset. There was
a plane starting to drop towards Torbay airport, about 100 km to the
SE. It cruised across the image for almost fifteen seconds -- you can
count its one-second flashes of the wingtip and tail lights, looking
like three-toed animal tracks, and as well see for a few seconds the
steady lights on the fuselage. Unlike the stars, of course, the
flashing lights of the airplane don't show any sidelong motion.

Much less obvious in the image than the plane's lights are some other
sharp marks: about a half-dozen short lines all moving in the same
direction (from upper right to lower left) and all ending in a
brighter light. The easiest to see is immediately below the centre of
the airplane's bright unbroken lines: make a rough equilateral
triangle down from the steady lines and look at its apex. The others
are the same length and sharpness and all have a bright spot at the
end; they seem scattered through the image. I am completely puzzled as
to their nature. When I saw the first, I thought "Meteorite!" but
having five or six identical ones puts the boots to that theory.

Because all of them are so similar, differing in brightness only, they
may be each a separate reflection of one thing, but I cannot figure
out what.

Got any ideas?