The landing strip theory is basically dead at this point and I think most serious researchers know it. The lines are far too shallow and the surface composition wouldn't support any kind of aircraft weight without just disintegrating. Von Daniken ran with it because it sounds incredible, and fair enough, it does sound incredible, but the engineering just doesn't hold up when you actually look into it.
What I find more compelling is the water/ritual procession angle that's been getting more attention lately. The Nazca region is brutally arid and there's decent evidence the lines follow underground water sources. When you're doing EVP work you start to appreciate how much ancient peoples tied spiritual practice to natural resource locations, it's actually a pattern that keeps coming up.
That said I don't think we should completely close the door on anything. We genuinely don't fully understand the culture. The landing strip idea is almost certainly wrong but whoever built those things had intent we haven't fully decoded yet, and thats what keeps me coming back to this topic. Anyone here looked into the geoglyph-as-ritual-path research? Curious what people think.