I can't believe it! I have been looking for this particular movie for 15 years and I finally found it! I've been keying in so many keywords but to no avail until yesterday. I became slightly smarter yesterday and these were what I keyed in.
"people in the plane vanish when they are not asleep, landed on an island and saw monsters, island disappears. 1980s show."
"plane landed on a mysterious island, chased by monsters, island then disappears on the last episode."
