WWW, both Dan Air and Air Europe were airlines serving the tour operator industry. One of Dan Air's weaknesses was that it wasn't tied to a tour operator, paradoxically Air Europe's weakness was that it was. It's parent company, ILG, went bust and Air Europe went down with it, even though it might have succeeded on its own. Viewed in this context both airline failures were part of the general decline of the tour operator market and the closest modern parallel is the failure of XL.
That doesn't really allow you to extrapolate their failures, which were decades ago and in a different market, into the low cost model of today any more than you could justifiably link the failure of Pan Am to the failure of Debonair.