Hello, Susan Myers.
Welcome to Microsoft Community!
Here, I would like to confirm the situation with you: your Bluetooth keyboard is affected when you are connected to Wi-Fi in a flight. You will not experience this issue when you are not in the airplane.
Please don't hesitate to let me know if my understanding of your situation is incorrect or if you have anything to add.
Based on the Surface Pro 8, you may be using the Surface Pro Flex Keyboard. have you enabled any networking tools such as a VPN during the flight? Normally connecting to Wi-Fi on an airplane shouldn't have an impact on the use of your Bluetooth keyboard.
I believe your device is not faulty, and this issue seems to have variables that we have not considered while in flight. A better understanding of the usage scenario can help us get closer to the truth.
I look forward to your further reply and always have your back.
Best Regards.
Leo.L - Microsoft Community Support Specialist