If the set up is with the app, then it's up to the app if it supports multiple devices. The watch, however, does not. If you set it up with a phone, it wipes out any data related to previous connections. It can only have one phone paired at a time, and anything related to any other connections is lost.
So, if airlink is just an app and it can connect to the iPhone from the watch without having to re-set it up to your current Android phone, then it'll be fine. But if it can only connect to whatever phone the watch is paired to, then nope, you won't be able to easily switch between phones.