The most obvious symbolism is that of the Christian Angels who are often depicted with wings.
Although the true purpose of the Wings of Light is unknown, both occur during an event where souls are involved. Presumably during Second Impact, the souls of the Katsuragi Expedition's team can be seen floating around when Adam spreads Wings of Light. During Third Impact, the souls of everyone on Earth are collected. It is speculated that the wings are a form of overcharged A.T. Field, since the Mass Production Evangelions are able to physically grab onto Unit-01's Wings of Light during the Third Impact.
Rebuild of EvangelionEdit
Wings of light are possessed by the four Adams of Second Impact and are later developed by Unit-01 at Near Third Impact during its transformation into a luminous being. When Misato observes the latter, she comments on the similarity.