Its such a clunky supplement and was poorly designed building off an uneven foundation. I gave it a legit shot and probably played somewhere between 3 and 5 games using the rules.
-The three flyer roles are all nerfs to their respective jobs as flyers and most flyers where never designed to fit those sorts of combat roles. Every individual flyer is weaker now and the only offset is reserve modifers if your opponent doesn't have a flyer in reserve.
- Flyer wings are
OP as gak. The Ignore Cover formation is so busted that it mulches anything your guns are designed to fire at. Also while Orks might be able to get away with spamming 3 Dakkajets (not the best unit but whatever) there is no zogging way to get 3 Space Wolf flyers on the table without risking turn 1 tabling from having nothing on the board. Flyer wings unfairly benefit spammable cheap flyers over the big tanky ones.
- Somehow of course the Eldar get the most benefit from this because
GW made the best added stat (agility) the highest on their stuff. Some of their stuff already has vector dancer so why the zog do they need to make turns on a 2+. Of course the Ork jets are zogging agi 2 because "ohh its an Ork, they must be clunky and slow"
- Pursuit value is a fairly garbage stat because who even cares about going faster in the movement phase (except for maybe bombers).
- The Agi and Pursuit values almost seem random as they don't follow much in the way of logic or consistency in how they went about assigning them to units. Ork supersonic jet fighter and ground straifer... Agi 2

Of course a Dark Eldar voidraven bomber is agi 4 because "Eldar" despite it being a zogging bomber. The biggest issue to this of course is these values have an in game impact and
GW made no attempt to try and balance these stats with a units points cost.
- Dogfight phase is all sorts of hot garbage with rock paper scissors like mechanics and multiple ways to disengage a fight resulting in a lot of roll offs to see if the fight happens.
- Reserve mechanics are busted because wings add something crazy like +2 to your reserves and -2 to their reserves. Feel sorry for armies that deep strike and don't have or want to use their flyers Poor Nids (daemons can zog off

) don't even have mechanical flyers.
- Combine the reserve mechanic with the wing mechanic and whoever goes 2nd will OBLITERATE the enemy flyers when they show up. :Here is the example: Player A goes first and his flyer wing shows up turn 2 (they all show up at once), those flyers do their dakka dakka dakka and things die. Player B now goes and would you look at that there aren't any enemy flyers in reserves so get dat +2 to reserves. Player B's flyer wing comes on in ignore cover formation and dakka dakka dakka down goes every enemy flyer. Player B has air superiority and there is next to nothing Player A could do because this supplement makes the 2nd turn flyer advantage even stronger while also giving a universal tool to
wtf murder any flyer in the game (ignore cover).
I think I have won every game that I used DftS using 3 Dakkajets and its always because I go 2nd and the jets murder every flyer on the board because of the ignore cover wing formation. In every game the dog fight phase has resulted in maybe 1 hull point lose but over 50% of the time it just ends up where the weaker flyer in the dog fight escapes the fight early or by the time everything is said and done no damage is dealt. Never destroyed an enemy flyer in a dog fight and never has it felt worth going through the dump mini game mechanics.
Every time I've played DftS its been vs Eldar flyer wings so its not like it was an unfair fight but it would be worse against armies like Space Wolves who really struggle at dealing with flyers and don't have cheap flyers to spam. Now my biggest nightmare is having to go up against an army that fully embraces the gak show that is flyer wings and does something classy like spamming Vultures.
Sorry to rant but DftS is a hot garbage supplement and almost comical in how badly they missed the mark. Even Forge World ,who I'm sure had a few head scratching sessions trying to figure out what
GW proper was thinking, was able to throw together some better flyer classifications than the 3
GW came up with but even that isn't enough to save this dumpster fire
I give it 2 exploding trukks out of 10.