Cossey and O'Regan consciously rejected a second-hand fleet, variable food and ephemeral expansion: from the late 1940s until the early 1960s a short-termist approach was typical for new independent airlines, being critical of the undercutting, opportunistic risks taken by Dan-Air, an airline that became highly diversified – many of its sectors never turned a profit. This weakness overwhelmed its management with activities that were seeing a negative return on investment. Dan-Air justified a diversification strategy by its low marginal cost as aircraft and crews were already available. For many years for Dan-Air each aircraft type represented a "cost centre line" that was financially accountable for itself.