I think the plane crash was before my time, at least as a college football fan. Was Marshall Division I at the time?
They were Division II when they came back (maybe even lower?), then moved up to I-AA, and now they're nominally Division I in the MAC.
Marshall is C-USA now, Division I.
Marshall wasn't Div II after the crash they spent a few years in the Southern Conference I-AA before moving back to Div I-A in 97. They were pretty much booted out of the MAC shortly after the crash for numerous violations. Marshall began a streak of winning seasons in 1984 that lasted until 2004, and had the highest winning percentage in the 90s of any Div. I school. The upcoming movie should be pretty inspirational in how the program rose from literally the ashes.