The landing strip theory is basically a relic of the 70s ancient astronaut craze and doesn't hold up to any serious scrutiny. The lines aren't reinforced, they're just scraped sediment, they couldn't support any kind of craft weight-wise. And some of them run directly into hillsides which is a fairly obvious problem if you're trying to land something.
That said I think dismissing the theory entirely as "dead" misses the point of why it captured peoples imagination in the first place. There's still genuine mystery around the scale and precision of the geoglyphs, the fact that they're only fully visible from altitude. The ritual landscape explanation is the current academic consensus and honestly it makes more sense given what we know about Nazca culture and water worship, but I wouldn't call the aviation theory "completely dead" so much as superseded by better evidence.
Anyone here looked into the work Reindel and Isla did on the settlement patterns around the plateau? Changes how you think about the whole thing.