Minor infringements are always punished with on the spot fines and many in the Fairy Kingdom complain that the traveller is being used as a cash cow to supplement the fairy government's revenues (something they deny, naturally). Those who can't pay up at once get zapped by the fairy squad (the degree of zapping and therefore pain is dependent on the seriousness of the offence).
Anything that causes a crash or injury to someone has to go before the fairy Courts and prison sentences are imposed. Fairy prisons are not pleasant places given they contain the dregs of the magical world who have been capable of killing and are really not the kind of people anyone with any sense would want to be locked up with.
Most in the Kingdom then take care to ensure any traffic offences they commit are minor. This has improved flying safety and has acted as a win-win situation for the government. (And they get more revenue).
Signs
These are based on our own Highway Code. The Kingdom saw no need to invent its own with the one proviso they needed signs to control traffic in flight. Stationary clouds are used to magically fix air based road signs to and it is an offence to tamper with these in any way. It is also an offence not to obey them. Red traffic light jumpers are always punished here and pedestrians are treated with respect (this is partly because everyone is a pedestrian at some point. Nobody spends all their time in the air).
It is compulsory to wait for roundabouts to clear, whether they are on the ground or in the air, before another vehicle enters them at all. This is to allow for the fact huge speeds can be reached on a broomstick and the only sure way to ensure a safe braking distance. Nobody disobeys this rule either. Mid-air collisions tend to be fatal, especially at speed.
The signs are more colourful than ours and some of them have "live action" cartoons on them to demonstrate what happens if you disobey them. (Mostly these are showing pictures of horrible demises as the main result of disobeying any Kingdom Highway Code rule is death. Cross a witch or wizard whilst out and about and it won't be the squad that punishes you). There are speed restrictions around the Queen's Palace and the bigger towns. The villages have a more relaxed attitude given the locals all tend to speed in and around their home area. (They take the view that if an accident happens, it means you weren't a good enough flyer/pedestrian in the first place and it serves you right for not looking where you were going).
All magical creatures have to take a theory and practical test based on whether they can fly or not. Those that can have to prove they can control their vehicle or broom of choice. Those that can't have to know the signs of when some flying idiot is about to crash in to them. Broomsticks, in particular, make a unique noise when they are failing and folk need to be able to recognize this.
Being able to hear a witch scream as she plummets to the ground is not deemed enough to pass the test - that just proves you've got good hearing. In any case screams can be misleading. There are many causes of screams in the magical world so being able to listen to the more subtle sounds of a broomstick or other vehicle is deemed to be more important. It's useful in any case as it gives you more time to get out of the way.
All need to know what every sign means. All need to be able to do an emergency stop on the ground or in flight.