I'm a hand luggage only kinda guy. Easy on, easy off, no faff with the conveyor at the end.
I'm a pretty good flyer anyway, so I just make sure I'm wearing something comfy, my AirPods are charged and I've got something I want to listen to on my phone. Depending on the length of your flight, I think it's always worth having a bottle of water to bring on from the airport, or buying one on board. It can get dry in the sky!
I have debated buying an iPad recently, not for flying/travel but just general usage - however, I think an iPad would be a great addition on a longer flight. Pop a movie on!
Water is a really good shout, but instead of buying a bottle at the airport (which can annoyingly expensive) you can bring an empty refillable bottle and fill it up after security!