Hi Eric,
It was nice to meet you,too.
There were lots of birds about, weren't there ? I was using a Canon 1D Mk4 and an 800mm lens. I usually set everything manually if there is a chance of flight shots, because while the exposure for the bird remains the same, the background can change so much. (And on "Auto" Exposure, obviously, a bright background makes the bird too dark.)
I used AI Servo, shutter speed 1/5000, f.6.3 and ISO 500 in the bright light. There's no right or wrong way to do it, but "blowing the highlights" is the big error to avoid if possible.
Even with the 800 lens these image crops are less than 25% of the frame area.
As for aggressive gull behaviour, they chase each other as well as smaller birds. Aggression must help them survive, even if it looks like robbery sometimes !