That’s it. I have installed Ubuntu many times connected over Wi-Fi without any problems, except one special case many years ago. In that case, the system had some brand new Wi-Fi adapter, so I had to install the driver over Ethernet. But in almost any case it just should work and you can simply try to get a wireless connection in a live sytem to find out. And as mentioned above, internet connection is not necessary while installing from USB stick with the usual image. Its just recommended to save time and install the latest updates of some components during the initial system installation. But of course, you can do it later and of course you can do it over Wi-Fi (except some very rare special cases as mentioned at the beginning).