I just spent half a day trying to get alias working in a script to no avail. Alias is normally, if not always a so call builtin command.
I have been attempting to use / learn Alpine Linux which defaults to sh/ash shell mostly builtin into Busybox. Unfortunately the bulk of shell documentation the web is based upon bash shell which is not suitable / outright incorrect with the nuances of sh/ash with busybox. Interestingly I found this reference that called using alias in this manner naive, PuppyLinux : AshCommands
I really like my ls command to be ls -la and always use alias for this.