I consider "Aikikai" to be more of an organization than a "style."
I hate using the word "style," but there are a lot of folks with differing opinions on how to teach in the aikikai. Some teachers say we must kiai during our techniques. Others say that we must always move 45 degrees off the line and move as though we were doing iaido. Others will contend that there is no "style" in aikido and that we must all find what works for us.
And so on.
Have you ever been to Aikikai Hombu Dojo and witnessed the very big variety of teachers there? It's pretty interesting...