Aires provide overnight parking just for camper vans. They can be found in most European countries.... But not in the UK, though a similar thing called "night stop" is being developed Some aires are just a lay by with no facilities and these are usually free.
But most have electric, water and waste disposal at a service point or bourne.
If electric is available there is not always enough for each pitch and so it is pot luck.
Toilets and showers are available on some of the aires, but only usually on the ones that charge. Most of the inland aires are free, but usually the ones in tourist areas charge around 2 to 12 Euros. Each Aire has a time limit that you can stay, this varies between 24 and 72 hour, although we have found that on some privately run airs you can stay longer.
This Aire is between a railway line and a busy road and so we didn't stay here- though it is fine if you have a big white van and sit in and watch Sky TV. We look for aires that we can sit out and enjoy the view. These vans are all out on a harbour wall and Libby is just visible to the right of the boat shed!
The aires are listed in several books and so you can plan ahead. Though if it says limited to 5 vans and it is the holiday season then it is good to have a contingency plan.
The biggest Aire we have stopped at had 120 vans! And the best Aire..... Is in a secret location!
We haven't found one yet that has WiFi and so we have to buy the occasional beer to use cafe wifi or McDonalds!
Hopefully from this you can get the gist of what an Aire De Service is all about.