The Light Hawk Wings are primarily a defensive shield capable of repelling almost any attack. They can also be used as an offensive weapon, with great results, but this is not their intended function. Z explains the true nature of the Light Hawk Wings later in the series; they in the Tenchi universe's manifestations of a higher plane of existence's energy.
The energy required to generate Light Hawk Wings is highly impressive. All Juraian ships can create Light Hawk Wings, though trees from the third and later generations of Tsunami's descendants must join forces to use them.