How do i turn off airplane mode on my apple watch

You turn this off in the Control Center. You can get to this by the watch face and swiping from the bottom of the watch to the top. If you are on any other screen, you can bring it up by holding your finger at the bottom of your watch and then when you see the control center start to come up, you can then slide toward the top of the watch and the control center will come up. There you’ll see the button with a plane on it, if it’s lit up then it is in airplane mode. Click on it, and it will turn airplane mode on or off.

This explains.

Use Control Center on Apple Watch - Apple Support