Is it possible to delete task from plan view?

I think it depends what you mean by "delete".  The notion of a plan is the work items targeted for a team for an iteration.  So changing the planned for iteration or the owning team will remove them from the plan.  You can change the planned for on the item menu actions, including multi-select.  In an Agile project, you might delete an item from the current Sprint plan by targetting it back to the Release or Backlog.  If by "delete" you mean resolve, then you would need to either edit the work item or add the Status column to your plan view.

Currently the plan Editor does not have this option.