All, thanks for your positive feedback!
Regarding the AF: all the photos are taken using AF.C and optical view finder. To be frank AF.C was one of the reasons I was so excited about that event as I wanted to verify how much KP AF it is better over K-5ii AF. Unfortunately I have never been shooting exactly this kind of event before with K-5ii BUT I feel like KP AF is vastly improved over the older SAFOX generation. Do not get me wrong - it is not perfect. But what I am saying is that KP really does some tracking especially in contrast with K-5ii for which it was hunting here and there to get some shot "accidentaly". Unfortunately I have never been shooting with K-3 generation so I cannot comment on differences with that one.
More details on AF settings: AF.C, AUTO 27, focus priority for both first and each next one, hold AF status - max (not sure if any other setting would change anything here); burst mode: continuous mode high. One note for continuous shooting with focus priority: definitely not 7 FPS, it was more like 3 to 5 FPS. SR was off.
And to describe better what I was shooting and how AF was working: I was shooting more or less perpendicularly to the line those guys were flying, say from 45 degree to the left to 45 degree to the right. So the distance was like ... hmmm .... 10 to 50 meters from me. More or less... I think
I was pretty lucky to get a seat in 4th row.
Some other settings: ISO 1600, time priority and 1/500 sec. The pictures were a bit undersexposed with F4 but that is not an issue for DNG format and good software nowadays.
Now I feel like I should have been trying even faster shutter speed but I did not want to boost ISO even more. The problem with me is that I have rather shaky hands and with my K-5ii I used to wonder if SR in my cam is broken... this does not help when shooting action and panning