自民國八十七年起，國內航空業者之虧損，表面上雖是肇因於市場破壞性競爭行為之結果，然其真正原因為何呢?本研究建構一模型來說明：在較高超額容量之情況下，業者傾向以價格競爭手段，來消化趨頓容量所造成之成本壓力。反之，則傾向採以較平和之價格策略因應。理論上，若業者之虧損是由超額容量所致，則政府順應業者要求而提高機票之票面費率，其恐將造成以犧牲消費者利益，來彌補航空公司決策錯誤損失之嫌。若此，則對市場容量施予管制，顯然的便有其實務上與學理上之必要性。相對的，若虧損是由破壞性競爭行為所致，則訂定一價格限制以維持市場之穩定，顯然的是有其合理性。而本研究結果顯示：在業者基於兩岸直航之預期，以致競相擴充機隊之情況下，過多航班致使業者之經營處於產出不具效率階段，才是造成市場陷於破壞性競爭行為之主因。

What are the real factors, other than the price war, that causes huge deficits for the domestic airlines? In this study, a model was created to demonstrate that airlines might set a more aggressive pricing strategy when the over-capacity condition is serious, under a less over-capacity condition while airlines might resort to a more peaceful price strategy. If the deficit is resulted from serious over-capacity problems, then to approve the increase of the regulated airfares will be an unfair play because it sacrifices consumers’ benefit to subside the carrier’s losses caused by wrongly expanding its fleet. Therefore, setting a policy to control the over-supply situation by reducing the approved flight numbers will be a reasonable mean theoretically and practically. In contrast, if the d,ψcit is caused by destructive price competition, then setting a stable price regulation policy will be a reasonable way to maintain the market mechanism. This study has shown that the expectation of relinquishing the banned cross-strait air transportation is the main factor that made the carriers optimistically expand their fleet. Consequently, the unrealized expectation had led to a badly superfluous flight condition and inefficent fleet operation. Eventually, the over-capacity situation triggered the carriers to engage in a severe price war trying to improve the revenue.