Wordpress - Redirection plugin - how to let the editor access the 'redirection' menu?

Update 2020

The original answer was of 2015, and the author has no affiliation with the plugin, so not aware of any changes to the plugin at all. You are requested to follow any updated helpful answer that might help you on this issue.

Original Answer

Good news is, from version 2.3.7 of Redirection plugin, they introduced a filter called redirection_role for the privilege. Here's is the core code (v.2.3.7):

add_management_page( __( "Redirection", 'redirection' ), __( "Redirection", 'redirection' ), apply_filters( 'redirection_role', 'administrator' ), basename( __FILE__ ), array( &$this, "admin_screen" ) );

###Solution Just put the following code into your theme's functions.php to enable 'editor' to get access to the 'Redirection' submenu:

/**
 * Redirection Plugin Editor access
 */
add_filter( 'redirection_role', 'redirection_to_editor' );
function redirection_to_editor() {
    return 'edit_pages';
}

See Editor user role and capabilities in WordPress - WordPress Codex