This might be one of the toughest things for a beginner photographer. Getting birds in flight is genuinely hard—they're moving across the sky and the light is all over the place. And if you weren't specifically out for bird photography, it gets even messier because you don't have time to fiddle with settings. Your best bet is animal AF with eye detection, SERVO for continuous tracking, burst mode, Tv (shutter priority), and a shutter speed of 1/100 or higher. That said, sometimes pure luck still gets you a pretty decent shot even when you mess up.
Let's look at a few examples.
This gull was flying away from the lens, so it was easier to keep in focus. With a moderate shutter speed I caught a nice moment and the image quality is solid (not amazing, but solid).
Here the AF did an awesome job and I got this shot of a purple heron. It was perched at first, then it spotted me and took off—so I was stuck with whatever settings I already had. I tracked it and… click! The cool part is this is basically the camera's SOOC JPEG, with barely any crop.
Reflection Luck counts too—and I mean a lot—with this kind of shot. Stick with it, be patient, and odds are you'll land a good one eventually…