Form showing "End tag form seen, but there were open elements." error when w3c validate

I am trying to w3c validate my page and I get "End tag form seen, but there were open elements." error. I have narrowed it down to the action="<?php echo $editFormAction; ?>" parameter, when I remove it completely the form sees the end tag, when it's in place it does not. I must have not closed something but I'm not sure what. I have included the form code.

Thanks as ususal

Tom


<form method="GET" action="<?php echo $editFormAction; ?>" id="quoteForm" onSubmit="return validateForm()">
<div class="col-md-4">
<h2 class="quote_title">Aircraft</h2>
<div class="form-group">
<div style="padding-bottom:5px;">
<select size="1" class="form-control" name="aircraftMake" id="aircraftMake" data-validation="required">
<option value="0">Aircraft Make</option>
<?php

$make=mysqli_query($link ,"SELECT DISTINCT(aircraftMake) FROM `aircraftData` ORDER BY aircraftMake ASC ");

while($row=mysqli_fetch_array($make)){?>
<option><?php echo $row["aircraftMake"]; ?></option>
<?php } ?>
</select>
</div>
<div style="padding-bottom:5px;">
<select id="aircraftModel" size="1" class="form-control" name="aircraftModel" data-validation="required">
<option value="0">Aircraft Model</option>
</select>
</div>
<div style="margin-bottom: 5px;">
<input id="tailNumber" name="tailNumber" class="form-control" type="text" placeholder="&nbsp;&nbsp;Tail Number" size="25" maxlength="100" value="" >
</div>
<h2>Engine</h2>
<div class="form-group">
<select size="1" class="form-control" name="engineModel" id="engineModel" data-validation="required">
<option value="0">Select Engine</option>
</select>
</div>
</div>
<div style="padding-bottom: 10px;">
<div class="form-group"></div>
</div>
<div style="clear:both;"></div>
<div style="margin-bottom: 5px;"></div>
</div>
<div class="col-md-4" >
<h2 class="quote_title">Your Info</h2>
<div style="margin-bottom: 5px;">
<input id="Name" name="name" type="text" class="form-control" placeholder="&nbsp;&nbsp;*Name" size="25" maxlength="100" value="">
</div>
<div style="margin-bottom: 5px;">
<input id="email" name="email" type="text" data-validation="email" class="form-control" placeholder="&nbsp;&nbsp;*Email Address" required size="25" maxlength="100" value="">
</div>
<div style="margin-bottom: 5px;">
<input id="telephone" name="telephone" type="tel" required class="form-control phone_us" placeholder="&nbsp;&nbsp;Telephone" size="25" maxlength="100" value="">
</div>
</div>
<div class="col-md-4">
<h2 class="quote_title">Additional Information</h2>
<textarea name="comments" placeholder="&nbsp;&nbsp;Additional Information" class="form-control" maxlength="2000" rows="4" style="width:100%; height: 106px;"></textarea>
<p style="font-size: 18px; padding-top: 20px; line-height: 16px; font-family: Arial, Helvetica, sans-serif;"></p>
<br>
<div style="padding-top:8px;">
<input type="submit" name="submit" value="Submit" class="btn btn-primary">
</div>
<input type="hidden" name="MM_insert" value="quoteForm">
</form>