:h 'laststatus', you can customize when you want your
:h 'tabline' to show.
:h 'showtabline', you can set the value of the variable showtabline to any of the following numbers with associated significance following those numbers below.
The value of this option specifies when the line with tab page labels
will be displayed:
1: only if there are at least two tab pages
So, in your case, you will need to set the variable showtabline to zero in order for it to be never shown. You can do that in either of the following manners.