Setting the Default Value for a dynamic select menu

Question

Hi I have a php page with 2 forms on it, one feeds the other to achieve a drill down (manufacturer > model). In the second select menu I have a default static value "Select Aircraft Model", I want to set a value for the first dynamic select menu to read "Select Aircraft Manufacturer". When I add a static value to my list it tells me I alreay have a dynamic behavior on this menu and to choose a different one. I have included the code for both menus. Thank you in advance, I know this must be a stupid question, but it's got me stumped.
Tom
//This is the menu I want to add the default static value to//
<td width="667"><select name="airMake" style="width: 200px;"onchange="this.form.submit();" id="airMake">
        <?php
do {
?>
        <option value="<?php echo $row_rsAirManufacturer['aircraft_manufacturer']?>"<?php if (!(strcmp($row_rsAirManufacturer['aircraft_manufacturer'], ((isset($_POST["airMake"]))?$_POST["airMake"]:"")))) {echo "selected=\"selected\"";} ?>><?php echo $row_rsAirManufacturer['aircraft_manufacturer']?></option>
        <?php
} while ($row_rsAirManufacturer = mysql_fetch_assoc($rsAirManufacturer));
  $rows = mysql_num_rows($rsAirManufacturer);
  if($rows > 0) {
      mysql_data_seek($rsAirManufacturer, 0);
      $row_rsAirManufacturer = mysql_fetch_assoc($rsAirManufacturer);
?>
      </select>
      </td>
  </tr>
</table></form>
    <form action="quoteResult.php" method="post" name="quoteForm">
      <table width="100%" border="0" cellpadding="5px">
        <tr>
          <td width="260"style="color: #000; text-align: right;">Aircraft Model:</td>
          <td colspan="2"><span id="spryselect2">
//This is the menu that works correctly//
            <select name="airModel" style="width: 200px;" id="airModel">
              <option value="" <?php if (!(strcmp("", ((isset($_POST["airMakeField"]))?$_POST["airMakeField"]:"")))) {echo "selected=\"selected\"";} ?>></option>
              <?php
do { 
?>
              <option value="<?php echo $row_rsAirModel['aircraft_model']?>"<?php if (!(strcmp($row_rsAirModel['aircraft_model'], ((isset($_POST["airMakeField"]))?$_POST["airMakeField"]:"")))) {echo "selected=\"selected\"";} ?>><?php echo $row_rsAirModel['aircraft_model']?>Select Aircraft Model</option>
              <?php
} while ($row_rsAirModel = mysql_fetch_assoc($rsAirModel));
  $rows = mysql_num_rows($rsAirModel);
  if($rows > 0) {
      mysql_data_seek($rsAirModel, 0);
      $row_rsAirModel = mysql_fetch_assoc($rsAirModel);
?>
              </select>

Answer 1

Change this -
<select name="airMake" style="width: 200px;"onchange="this.form.submit();" id="airMake">
to this -
<select name="airMake" style="width: 200px;"onchange="this.form.submit();" id="airMake">
<option value="-1">Select Aircraft Manufacturer</option>
Then if the value of 'airMake' is -1 you know that no choice was made.