I'm going on an airplane for the first time next month. What is to be expected?

I'm in my mid-20's and am fortunate enough to be going on my first holiday overseas in a month! However this does mean using an airport and travelling by plane; something I've never done before. I'm only going to the Netherlands, so it's 1-2 hours in the air, nothing major for my first trip. Yet I'm nervous and unsure what to expect. I have minor claustrophobia and the idea of being in the air, with no way to leave the plane until it lands sounds pretty scary. My partner keeps comparing it to a train, but if you push an emergency stop button on a train it...stops. On land. You can just kinda leave if you really have to. But you can't do that on a plane, and that's slightly worrying. But yeah, just wondering what it's like. How early should I get to the airport? How many queues will there be? What's flying like? Edit: thank you all for your thoughtful (and funny) responses! This has been very reassuring and I'm definitely more excited now, my window seat is booked there and back, and I'm staying at a hotel next to the airport the night before so I don't have to stress about getting there (flight is at 8am). And I will be sure to clap when the plane lands ;)