NOTES:
It should be noted that the hollow earth case is one that a lot of authors get wrong. There is no gravitational force felt inside a really hollow sphere - so stories in which people are standing on the inside surface are wrong. On the other hand, if the sphere has an internal atmosphere, then there will be a small gravitational force pulling inwards, as Hal Clement noted in Still River.
By the way, the size of the black hole holding all the earth's mass is pretty small (2GM/c/c=0.44 cm), so missing it by a few miles keeps you well away from its event horizon and keeps your maximum speed well less than light speed (no relativistic effects), but tides might be a problem (see tide equations on upcoming pages).