...Does anyone know if
INS is still used on civilian airliners, particularly on overseas
flights?


Trans-oceanic or polar flights are about the only place you'd need one,
anyway. When I last flew (mid-90s) my employer, a non-sked freight
hauler,
was looking into converting from INS to GPS. I'm guessing there aren't
many
INSs left, at least on US registered craft.


I got a cockpit tour of a United 767-300ER in year 2000 that was used for
overseas international flights. Crew said they have 3 INS units on board.