File talk:Falange española Yugo y flechas.jpg

I think the original meaning of this symbol is the merging of the Kingdom of Castile and the Kingdom of Aragon into the unified Kingdom of Spain. Castile + Aragon = Spain.

Queen of Castile = Queen Isabella I   = Isabella name starts with "I" which is equivalent to "Y"

King of Aragon  = King  Ferdinand II  = Ferdinand name starts with "F"

"Y" represents Castile = "Y" is Yugo in Spanish and Yoke in English

"F" represents Aragon = "F" is Flechas is Spanish and Arrows in English

So the this symbol represents Spain as the result of the unification of Castile and Aragon. Unfortunately today most of the spaniards associate it to Falange but the fact is that this symbol is 500 years old.

See the wikipedia article "Catholic Monarchs" for more information.