Whilst I agree with Nick, I find myself being sucked in! The T-Mobile wifi works pretty well It’s around £25 for the whole flight and I have always been able to work, bar one flight to JFK and I did get a refund due to patchy service.
It is £10 for one hour and about £3 for messaging for the whole flight which works pretty well. I use it for text, whatsapp and Teams. These prices are form last night JFK to LHR. Happy flying!