Complex sentence: From the 1970s to the early 1990s, various plans surfaced to try to build such a link, while the JFK Express subway service and shuttle buses provided an unpopular transport system to and around JFK.
Split into simpler sentences: From the 1970s to the early 1990s, various plans surfaced to try to build such a link. Meanwhile, the JFK Express subway service and shuttle buses provided an unpopular transport system to and around JFK.