Jumping right in with your form intersections, your work here is demonstrating an understanding of the relationships between these forms as they exist in 3D space that has been developed quite nicely. I'm not seeing any notable mistakes or issues, and given that this exercise is an excellent litmus test for the core understanding this course is meant to develop, that is a very good sign.

Your cylinders in boxes are for the most part similarly well done, although there's one point I wanted to mention - I noticed that you used your ellipse guides for this one, which isn't itself a problem. I did however want to advise you that when you run into situations where an ellipse guide doesn't quite fit what you need perfectly, generally you're going to want to freehand your ellipse, as the alternative would mean changing what's being drawn in favour of the tools you have, which can depending on the situation alter the exercise and its benefits. In this case, your ellipses were generally pretty close even in the cases that they didn't touch all four edges perfectly, and so it's fairly easy to extrapolate to where those contact points would actually fall - but every additional extrapolation does reduce how accurately the ellipses' line extensions describe the proportions of the plane enclosing it.

Continuing onto your form intersection vehicles, these are fantastic. It's pretty common for students to overestimate how complex this exercise needs to be, and that can interfere with how effectively they absorb the core purpose of it (which is to remind us that, even though the more detailed constructions involve a lot of subdivision and forests of lines, which can make it seem like the object only emerges towards the end, we're still building up our constructions from simple, starting with the bounding box, and gradually carving it down to add complexity, like carving wood as opposed to building it up out of toothpicks). You however stuck to the assignment as written without embellishment, and so you've done a great job of focusing on the core primitive forms.

And finally, your more detailed vehicle constructions are by and large done quite well, although there are a couple key points I want to mention that'll help you continue to get as much as you can out of these constructional drawing exercises.

Firstly, while as a whole you've made very effective use of the orthographic plans, I did notice that you appeared to have a point at which elements smaller or less significant than a certain threshold were not established within the plan (in terms of using subdivision to identify exactly where they should be placed - they were just drawn floating there, leaving you to approximate their positioning when drawing those elements in the 3D construction).

Ultimately the thing to keep in mind, generally in regards to everything we're doing throughout this course, is that it's all about the process, and how it rewires the way in which our brains tackle problems. By being hyper-intentional in applying the techniques here as thoroughly as possible, we little by little influence those natural tendencies, so that when we draw our own stuff, we can allow our subconscious to worry about the majority of the "how do I draw this", so our conscious brains can focus on what it is we wish to draw, to make all of the design choices, and so forth.

As far as the orthographic plans fall into this, it's about separating the decision making from the execution - just as the ghosting method does for our freehanded marks. We aren't bound to recreate the reference image we're working from completely - it's just a source of information, we get to decide what we include and what we leave out. And so, if we decide that a door handle isn't that important (at least, not enough to warrant identifying its specific location), then it's fine to leave it out of the final construction as well. But, if we decide we want it to be in that final construction, that's enough to warrant defining the landmarks upon which its positioning would be established.

Admittedly not all of my own demos do this. The course has evolved over the years, and so this heavy use of orthographic plans is something we've steadily focused on more and more, but will be integrated into the lesson content more completely when our video/demo overhaul reaches this far as discussed here). So this is definitely a case of "do as I say, not as I do" to help you better apply these exercises in your own future practice.

The second point I briefly wanted to touch on is just a reminder that as discussed here in Lesson 6, it helps a great deal to first establish your curves with a chain of straight edges (since that would introduce corners which can be plotted out on the orthographic plan), and only round it out at the very end.

Aside from that, your work is coming along great, and you've clearly internalized the core principles of this course to great effect. I'll go ahead and mark this lesson - and the course as a whole with it - as complete. Congratulations!