“Is aggression a symptom of ADHD?”

For the most part, aggression is not a symptom of ADHD. However, sometimes children can become aggressive as a function of their frustration.

Many children with ADHD may exhibit aggression because of difficulty controlling impulses, regulating their emotions and lack of coping strategies or routines. The behavior has to be conditioned into a more positive behavior. Ie. using nonverbal signals like peeing hands to the side of on lap to stop hitting. Lightly removing hand or tap desk when child grabs. Creating a virtual chart, song or sound during transitions between activities. The caregiver has to be consistent and patient and remember that it takes at least 3 weeks to form a new habit.
Go to Therapistaid.com and look up the above mentioned skills.

Aggressive behavior may arise as a result of difficulties in impulse control, emotional regulation, and frustration tolerance, which are commonly associated with ADHD. I would also urge you to seek out a consultation with a therapist to rule out other possible issues like anxiety or depression, which usually present with ADHD.

Those with ADHD symptoms displayed more severe aggression than children in the control groups. Externalizing behavior problems and aggression, which increased as ADHD symptom severity increased, appeared to be related to the hyperactivity-impulsivity ADHD domain.

See this link...
https://www.trisadhd.com/about-adhd/?msclkid=1a5a1da51eb4197a9c6d7c4c6b7e7838
and
https://www.healthline.com/health-news/how-can-we-help-children-with-adhd-control-aggression-121114#:~:text=Children%20with%20ADHD%20have%20trouble%20sustaining%20attention.%20They,with%20aggression%20and%20defiance%20in%20children%20with%20ADHD%3F