Yes, you can pick up plenty of graduate engineering classes online. Enough of them are all theory, an M.S. is doable online. Georgia Tech is another place you can check out for that edprush.
However, none of this gets you the B.S. Zebo already went into this, but what's your math background? You do realize that engineering undergrads take a full year of calculus before they can even get into most of the basic engineering classes, right? And you will have to take some other math courses, like vector calculus and differential equations before you can get very far in your major. A *signficant* number of people wash out from taking all these prerequisites.
That being said, I don't see why you theoretically couldn't take these basic math courses online if you can find them. However it would be insane IMO. A large part of the engineering experience is collectively suffering through and working in study groups, or at the least having a couple buddies you can call to bounce problems off of. You know, the problem you've stared at for an hour and a half and are lost on. Depending on the person, you can plow through much of it on your own, but I haven't met anyone who did it all completely alone.
What about chemistry and physics? You have to take those in the first 2 years of a normal B.S. program, and they have labs.
Once you have preliminary stuff out of the way, then really get into your major. And that's where you get stuck with lab after lab after lab. Most of this stuff is structured as team work as well, it doesn't lend itself to independent online assignments, even if you did have a wind tunnel in your garage.
I don't see how you can do a B.S. online. I'm not disparaging the idea of online learning either, I just don't believe it's possible to earn a real B.S. degree without ever setting foot in a lab, given the structure of accredited engineering programs. If your goal is to get an engineering degree, I think you'll have to spend at least a few years as a full time student at a university.
If you find a place that offers an online accredited undergrad degree, post it here, we'd all like to see it.