At the moment, all civilian and military flight routes are oriented north-south. Any east-west air activity, particularly from the direction of mainland China, can thus be easily spotted on radar screens. If Taiwan opened direct transportation links, it would cause confusion in both civilian air-traffic control and military strategic command, and would also add an element of porosity to Taiwan's air defenses.
軍方評估，目前民航機航線與我戰機皆採南北向飛行，對岸若有東西向直飛的動作，雷達極易偵查，但未來若開放兩岸最短距離直航，除了可能形成民航地面管制與戰略上的混淆，也會出現空防死角。