And how does recoil affect them in the air.
Yeah, recoil on an airborne pixie would be brutal, because they would lack any stability from their feet being planted on the ground. Their lack of mass means that they would be subject to far more acceleration from the force of the recoil than a full-sized person, and without friction between their feet and the ground to hold them still, they'd be even more likely to be sent backwards. Yes, they could try to resist it by providing forward acceleration with their tiny little wings, but they're not exactly possessed of a lot of thrust, and even if they were they would still be more stable if they planted their feet
and used their wings.
And that's not even getting into the issues that would result from the length of most handguns being almost half of their height (a Beretta 92 is 21.7 cm long compared to their heigh of 45 cm, and even a subcompact Glock 26 or 33 is 16 cm), even before any sort of stock was attached, and the grip (which can't really be made smaller because it contains the magazine) would be far bigger than their tiny hands could wrap around.
They'd either have to build their own tiny guns (with comparatively tiny ammo, most likely) or attach new grips and stocks in their own size to the tiniest of hold-outs to produce some sort of bulky, awkward quasi-rifle. Either way it wouldn't have much power, because at one-quarter the height of a human (and thus something like 1/64th the mass) they wouldn't be able to handle anything powerful.
Good thing they're all Awakened.