Note that many decks use the association Swords-Air, but a small minority of decks use the association Swords-Fire. I have provided associations for both of these systems, with the first entry being for Air, the entry in parentheses for Fire.
Ace of Swords

Also: Spades, Daggers, Spears
Element: Air (sometimes Fire)
Astrological Signs: Gemini, Libra, Aquarius (sometimes Aries, Leo, Sagittarius)
Season: Autumn (sometimes Spring)
Direction: West (East)
Social Class: Knighthood and Noble classes
Style: confronting, striving, freezing, conceptualizing
Jungian Function: thinking
Associations: strife, tension, travel, communication, logic, detachment, mental activity, legal action
Images: sharp objects (i.e. knives, swords), sky, clouds, sylphs, birds
Occupations: lawyers, judges and other legal professionals, travellers, intellectuals, journalists and other communicators
People: brown or black hair, light eyes, olive complexion
Virtues: strength, courage, truth, justice
Vices: fear, confusion, thoughtlessness, judgmental