If you are trying to model this plane in its final resolution from start to finish, then you are asking for a lot of headache. Keep the poly count at a medium resolution and apply Meshsmooth to handle the high-resolution.
There are few caveats with Meshsmooth/Subdivision modeling:
Try to keep your polys in quads (4-sided polys) as much as possible when preparing your model for Meshsmooth. Don't worry if you end up with non-quads at some point. You always will. Just make sure to adjust them as you go. Each iteration of Meshsmooth will subdivide each poly by 4, which means your model's poly count will become heavy, so you need to be mindful of this as you model in low or medium res. However, many smoothing artifacts should go away unless you have extreme angles with very few polys between them.
The reason for the "tearing" around the holes after applying Meshsmooth is because you have not enough polys/edges around the holes. When you have open edges when modeling for sub-division, you'll need to add more rows of polys where the opening is so that it creates an anchor. I would close those hole during modeling and open them later. Also, your model has a lot of 5 to 6-sided polys. These polys, when subdivided with Meshsmooth, will create what may look like "tearing" or bunching and create messy lines. Try to make them 4-sided while keeping clean lines.
You always need to add more rows of polys around sharper angles, corners, and curves. Otherwise, applying Meshsmooth to the model will melt it.
🙂 For example, create a Box with 1 segment (1 is minimum) in Length, Width, and Height, then apply Meshsmooth. Your box will melt and look like a blob. Go back to your Box and increase the segments to 4. You should start seeing the shape of a box with smooth edges.
The trick is to model in as low resoultion as possible without losing the integrity of the model when Meshsmooth is applied.
AREA has some basic Poly modeling tutorials that you may find useful. I'll try to dig up some links and examples for you.
