I am trying to find out how can I check to see if my visa has been cancelled or not before my flight. I've noticed someone's was visa cancelled the day of their flight at the airport so I am pretty nervous. How can I know if my visa is still safe?
I will repeat as an answer: your visa is not cancelled. That almost never happens.
I've noticed someone's was visa cancelled the day of their flight at the airport
I daresay you are confused about what happened or they had some extraordinary circumstances. Visas do not get just cancelled out of thin air. Your visa might get cancelled / revoked at the border but also only for extraordinary circumstances. You can read the regulation yourself. Serious illnesses, drug trafficking, terrorism and the like are reasons. I think you might've noticed if you took part in genocide lately. The least serious but logical thing to happen is people filing for an immigration visa, that can cancel their B1/B2 yes. But that makes sense, doesn't it? By filing for an immigration visa you certainly have stated your intent to stay in the USA so they don't want you to get in as a visitor and disappear.