Apple's wireless AirPods headphones could see massive growth over the next few years, TF International Securities analyst Ming-Chi Kuo wrote in a research note released last week. It's a positive sign for Apple as it seeks new growth areas that can help the company squeeze more revenue out of each iPhone user.

Kuo, who has a track record of accurately predicting Apple product launches, said AirPods are Apple's most popular accessory ever.

In the note, Kuo said Apple AirPods have the fastest growth momentum of any Apple product. Kuo estimates Apple will ship 26 million to 28 million AirPod units this year, up from 14 million to 16 million in 2017. Kuo also expects Apple to release a new version of AirPods next year with wireless charging that will help propel shipments to 50 million to 55 million units next year, 70 million to 80 million units in 2020 and 100 million to 110 million units in 2021.