Hello!
1x1 Pilot: This isn’t just to do with the pilot, but since the beginning, Aria has been the main focus since she is the only liar to do the ‘shh’ in the opening sequence. Maybe this suggests she is the center of attention, thus, head A.
1x4 Can You Hear Me Now: Aria takes interest in the typewriter as Ezra’s apartment as she spends a lot of time there. In the same episode, Aria vows to tell her mother about her fathers affair, but A beats her to it with a letter made on a typewriter.
1x12 Salt Meets Wound: I used this for my Ezra theory but it’s actually really relevant to the Aria theory. Aria is explaining to Ezra who wrote the note on the car, and that it was Noel Kahn. At the time the other liars believed Noel was A, so to keep the story straight she agreed that the person writing on the car was A. As she explains to Ezra, the camera keeps panning to him with the blackboard behind him, and Aria’s explanation with the words that stand out on the board, she would be saying “I know who wrote that message on your car. [It was A] It was Noel Kahn. […But I was A].
1x13 Know Your Frenemies: Just as Noel Kahn was about to go to the principal about Aria and Ezra, A set him up to look as though he’d stole test answers. It usually looks as though the sort of thing A would do would be to expose Aria and Ezra’s relationship. Aria and Ezra have also had their relationship threatened many more times but A finds a way of helping them.
2x2 The Goodbye Look: Mona refers to Aria as ‘Big A’. Aria and Mona never really seemed friendly so it’s not like they have nicknames for each other. Mona could’ve referred to Aria as the main A, or the boss without anyone noticing because no one suspects Aria of being A or part of it. Aria also knew Mona was calling her as she rolled her eyes, if they weren’t really friends with nicknames, how did Aria know she was ‘Big A’?
2x18 A Kiss Before Lying: Aria admits to having lied to her friends, in context she means about Spencer not telling Hanna about them all working on A’s videos, out of context looking like she was talking about Ezra. However, she is notorious for keeping bigger secrets, for example, her friends didn’t know about her relationship until the 11th episode.
2x20 CTRL:A: A sends another letter written on a typewriter, but this time to Byron, cluing him in to the
whereabouts of Aria and Ezra. Conveniently, Aria cancels and Byron shows up, and Ezra leaves as soon as he
sees Byron, saving Aria and making it look like someone is out to get her.
2x22 Father Knows Best: At the end of the episode, Aria mentions she’s cold so puts on Alison/Vivian’s red coat that was in the back of the car, this was the last time we saw the coat.
2x22 Father Knows Best: The other liars say Aria is best at lying to the people she loves. Aria agrees to do the task but it’s been mentioned multiple times Aria is good at keeping secrets, best at lying, could turn against her own family etc, maybe Aria is keeping the biggest secret from them all: that she is the head of the whole A thing.
2x22 Father Knows Best: To stop Ashley looking for answers, Aria tells her that she herself is A. Aria could
have done this to stop Ashley delving into A’s secrets to save herself and the rest of the A team but it looks like
she is protecting Hanna. Again, no one really would suspect her as A so they assume it’s just a careless lie,
but of course, Aria is the best at lying to the people she cares about.
2x25 UnmAsked: At the end of this episode, Mona is visited by who we assume is the ‘main’ A, who is wearing
a red coat. Marlene King stated that there is one A who has helpers known as A also, Aria could be this main A.
Spencer also finds A’s sketches of their costume, saying they’re going as the Black Swan, after googling, there is an alternative look to a Black Swan costume used to advertise the Natalie Portman movie.