I am about to join and I am trying to get some info on the 21B and 21E MOS's. I want drive front end loaders but I also want to break down doors and go on patrols. Do heavy equipment operators get to act like infantrymen? I would really like to go Airborne and I don't know which MOS would more likely take me there. ANY info would be much obliged. Thanks!

I am a Bravo by title but i was sent to an Echo unit since they were deployed and were understrength. I have been able to experience both MOS's and i will tell you, in my opinion, a little about both.

21E-
your AIT will consist of learning to operate equipment as well as leraning how to properly maintain it.
you will be able to operate many different types of heavy equipement(dozers, loaders, scrapers, rollers as well as 916 tractor trailers, 5 ton cargo trucks, HUMVV's etc.) as well as some 21J equipment (Hydrolic Excavators, vibe rollers, cranes etc.) as an echo you wont be kicking doors in or doing any patrols, you will most likely be doing contruction projects which can range from a couple of days to a couple of months. this can mean mean in the middle of nowhere enduring the wonderful weather that the middle east has to offer (freezing winters and scorching summers). echos main job is operating equipment and maintaing it. however echo companies have thir own security during movements which means they need guntruck gunners, this is the closest youll get to being a 21B in an echo unit (unless you get hit during a construction project =).

21B:
your AIT will consist of learning about explosives as well combat squad tactics and movements, pretty much infantry with explosives. you can wind up in a mechanized unit which deals with buffalos and some heavy equipment etc. their main mission is getting rid of roadbombs and keeping roads oparation capable.
a light unit deals with kicking in doors and doing foot patrols, now granted any of these units can be asked to do either of these at any time, im just trying to give you an idea.

personaly, i like being a 21B better than a 21E. I chose 21B as my MOS and expected to kick in some doors, i was put in a position where i got to experience 21E as well but being deployed gave me a chance to see what both MOS did during deployements.
21E would be a good MOS if you want to do this after the army. but be warned 21E is an EXTREMELY tiresome MOS you WILL be working long hours and the chances of seeing combat will not be as good as a 21B, also to make E-5 their promotion points are alot higher than 21B. on the other hand 21B is a dangerous MOS, in the civilian side there isnt much to do with 21B skills (except maybe quarry demolitions or something like that) but you will get to kick some doors in and promotion points are almost half of echoes.

well i hope this helped you or anyone else that is considering any of these 2 MOS's, i hope my answeres werent too opinionated but if you have any questions post them and ill do my best to answer them.