The bootstrap 3 docs for horizontal forms let you use the .form-horizontal
class to make your form labels and inputs vertically aligned. The structure for these forms is:
<form class="form-horizontal" role="form">
<div class="form-group">
<label for="input1" class="col-lg-2 control-label">Label1</label>
<div class="col-lg-10">
<input type="text" class="form-control" id="input1" placeholder="Input1">
</div>
</div>
<div class="form-group">
<label for="input2" class="col-lg-2 control-label">Label2</label>
<div class="col-lg-10">
<input type="password" class="form-control" id="input2" placeholder="Input2">
</div>
</div>
</form>
Therefore, your form should look like this:
<form class="form-horizontal" role="form">
<div class="form-group">
<div class="col-xs-3">
<label for="class_type"><h2><span class=" label label-primary">Class Type</span></h2></label>
</div>
<div class="col-xs-2">
<select id="class_type" class="form-control input-lg" autocomplete="off">
<option>Economy</option>
<option>Premium Economy</option>
<option>Club World</option>
<option>First Class</option>
</select>
</div>
</div>
</form>