In Web TimeSheet, Time Off requests are not raised against or associated with Projects. A user can work in any number of Projects and, each project will have its own Project Manager or Project Leader.Hence, the System will not know which Project Leader should approve the requested Time Off.
There is no association between a Time Off raised and a Project / Project Leader in Web TimeSheet. Hence, all the Time Off request usually goes through the users Supervisor. In the timeoff approval path set up, the drop down does not list Project Leader.
You can add a specified user in the timeoff approval path, who happens to be a project leader.