a cross country flight is not over until you return home.

Nope.

Suppose I fly 200 nm and land, discover the paint on the aircraft is scratched,
and call the FBO to tell them the airplane is unflyable until it gets fixed. I
take the train home.

I log this as a cross country flight. The flight is over.

The FBO has one pilot fly another pilot over to the airplane, and then flies
back alone. She logs that as one or two flights. She might even log it as
part of a flight (if she's on the way somewhere else - her call). The other
pilot (the passenger) then inspects "my" airplane and determines that I'm a
wuss for being afraid to fly with a scratch in the paint, but the gash in the
wing needs some attention. The wing is replaced, and he flies the plane
another six hundred miles to get the new wing painted. This will take three
weeks, so he too takes the train home, logging it as one flight. He does three
weeks of flight instruction (seventy three flights) and then takes the train
back to the airplane to fly it home, but in that time the FBO folded and the
plane was sold to a chap in Duluth, four hundred twelve miles away.

He flies it to Duluth. The new owner flies him back to the airport where his
FBO once was (and hopefully his car still is) and then flies back to Duluth,
the new home of the airplane.

So, by your rule above, how many never-to-be-completed cross country flights is
this airplane still flying at the same time?

Jose

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