BT TV boxes will work without a Freeview aerial connected, but you'll be missing out on lots of channels and some On Demand services. You'll need to connect your aerial and scan your channels in order to receive all of your On Demand services.
Can you use a BT TV box wirelessly?
Yes, all BT TV packages come with broadband. The new BT TV box is wifi-enabled, allowing for a wireless connection with your hub.
How is BT TV installed?
https://www.youtube.com/watch?v=313RzRJ7JDA
How can I watch TV without an aerial?
The best option for watching a TV without an aerial is to connect your TV to your router or broadband via an ethernet cable and use the built-in streaming apps.12 Sept 2020
Does YouView box need an aerial?
Also, don't forget that YouView uses Freeview and not Freesat channels. You need an aerial instead of a satellite dish.9 Jun 2020