California Plumbing Code (where I am) states that all indirect waste pipes shall discharge into the building drainage system through an airgap or airbreak. I have an air conditioner condensate drain that I would like to connect to a sink tailpiece (between p-trap and sink). Is there a fitting with tee'd air gap by a manufacturer that I can insert into the pipe between the sink and p-trap, for the A/C condensate drain to drain into, and is there a name for that style of fitting?

Your code is too strict for most of us but I think Milo can help when he reads this. I think what you describe will not be accepted by CA code, it is not indirect.

California Plumbing Code (where I am) states that all indirect waste pipes shall discharge into the building drainage system throught an airgap or airbreak. I have an air conditioner condensate drain that I would like to connect to a sink tailpiece (between p-trap and sink). Is there a fitting with tee'd air gap by a manufacturer that I can insert into the pipe between the sink and p-trap, for the A/C condensate drain to drain into, and is there a name for that style of fitting?

I checked the code again and found that an airbreak is acceptable in place of an airgap. Since a wet p-trap should act as an air break I guess no air gap fitting is needed.

California Plumbing Code (where I am) states that all indirect waste pipes shall discharge into the building drainage system through an airgap or airbreak. Isn't that odd? UPC is the strictest most nit-picking code we have and yet they mandate dumping liquid that is neither sewerage or gray water into the city sewer system. In my area of Florida it's illegal to do this . The reason being that they would have to process all that extra water at considerable expense. I'll never figure out UPC.
As for your idea you're thinking of a branch tailpiece, (see image), however I don't know if UPC will recognize this as a air break. Milo? Mygirlsdad? Where are you? Tom