asianredneck, some expeditions have air bag suspensions on them. Depending on the options that your truck was ordered with will depict if you have airbags or not. In short, if you have an EB, then you will have airbags in the suspension. If you have a 2wd truck, then you will only have airbags in the rear. If you have a 4wd truck, then you will have airbags in the rear with air shocks up front.
Plaese keep in mind that you can find EBs with a standard suspension (ie, no air bags) as that was an option. LIke you can find XLT's with a full air ride suspension on them. SO, there is no clear cut method to determining if your truck should have airbags or not short of getting a copy of the original build sheet for your truck and seeing what it says.
Some members have even gone as far as to remove the air bags from their vehicles due to past issues.
Is there something specific you are wanting to know about this setup? I'm sure someone here can answer it for you.