I get an error message when trying to implement geom_xspline with
plotly.

I get the desired graph in ggplot2 but the plot cannot be converted to a
plotly object when using the ggplotly function.
You can find the code showcasing this below.

library(pacman)
pacman::p_load(tidyverse, datasets, plotly, ggplotly, ggalt)

# airmiles built-in dataset: 
airmiles <- datasets::airmiles
year <- 1937:1960
airmiles <- data.frame(year = year, airmiles = airmiles)


# "line" plot using geom_xspline from ggalt package: 
plot_airmiles <- ggplot(data = airmiles, 
              aes(x = year, y = airmiles)) + 
  geom_point(alpha = 0.75) + 
  geom_xspline(spline_shape = -0.7) +
  scale_y_continuous(n.breaks = 10) 

plot_airmiles

# interactive plot: using ggplotly doesn't work
ggplotly(plot_airmiles)

Could this be implemented in plotly? Is there any way I can still
produce the interactive graph in plotly without waiting for this to be
implemented?

The plotly documentation (https://linking.plotly-r.com/custom-geoms)
mentions the possibility of creating custom geoms and using the
to_basic() function from the plotly package to “convert” the custom geom
into a geom plotly understands.
In the link above, the authors provide an example for geom_xspline
specifically but their method and code don’t work unfortunately.