At most major airshow locations, the position of the flight line really makes 400mm a MINIMUM focal length. The new 150-600s from Sigma are looking to be very good choices for airshows. The Tamron is not so good as the VC won't work while panning at the slow shutter speeds that you need for propellor aircraft, or worst of all big helicopters. I usually find 1/160 will give decent prop blur, but for helicopters 1/100 might be Ok for a smaller one, but something big like a Seaking needs 1/60 or even slower if you want a the main rotor to produce a full disk.
I decided to have a quick look at your settings before I posted the above. You really need to be using higher shutter speeds with the jets. For jets I would always try to go for 1/1000 or faster. In this case I would have gone for 1/1000 and f/8 and upped the ISO until I got the correct exposure. It's only the propellor driven aircraft that need these slow shutter speeds to look good. Your panning did indeed get better as you went on. The higher shutter speeds just make the panning easier. This is especially true when using a longer more suitable lens.
As I cannot afford to have a really long lens sitting around I usually rent one for the weekend when I will be shooting a major show. That's actually a really good way to do it if you are only shooting one or two shows a year.
Alan