Is it possible to pass a Field value Via URL when creating a Node?
For passing values to forms:

There is a Drupal Module called Prepopulate which allows you to prefill fields on node forms using $_REQUEST variables. 

It is quite simple to use and merely requires you to rewrite the links to contain the field values you want to pass along. If you want to fill field_your_fieldon your ticket node, the link would need to look like this:

http://www.example.com/node/add/ticket?edit[field_your_field]=desired field value




That said, this wont hide any fields on the form, merely provide default values for them. If you want tickets with different fields, you could always use multiple node types. 



If you want to actually hide fields based on the url, you could reuse the node form on custom pages and manipulate their fields there as you need.

You will  need menu entries for your different node displays to distinguish which node form you want to call.

function ticket_module_menu() {
  $items['ticket/add/tech-ticket'] = array(
    'page callback' =&gt; 'drupal_get_form',
    'page arguments' =&gt; array('ticket_module_tech_ticket'),
    'access callback' =&gt; 'create ticket content', //or put a custom permission
  );

  $items['ticket/add/support-ticket'] = array(
    'page callback' =&gt; 'drupal_get_form',
    'page arguments' =&gt; array('ticket_module_support_ticket'),
    'access callback' =&gt; 'create ticket content', //or put a custom permission
  );

  return $items;
}


And then create a form for each entry:

function ticket_module_tech_ticket() {
  module_load_include('inc', 'node', 'node.pages');

  //get node add form for node type ticket
  $form = node_add('ticket');

  //Hide fields you do not want to display
  $form['field_your_field1']['#access'] = 0;
  $form['field_your_field1']['und'][0]['value']['#disabled'] = TRUE;

  return $form;
}

function ticket_module_support_ticket() {
  module_load_include('inc', 'node', 'node.pages');

  //get node add form for node type ticket
  $form = node_add('ticket');

  //Hide fields you do not want to display
  $form['field_your_field2']['#access'] = 0;
  $form['field_your_field2']['und'][0]['value']['#disabled'] = TRUE;

  return $form;
}