title: Django filter query with date and integer
body: <p>I try to write query which must show planes, which working life is over.
  Models.py</p>
  
  <pre><code>class Aircraft(models.Model):
      registration_num = models.IntegerField(primary_key=True)
      airplane_age = models.IntegerField()
      commision_day = models.DateField() 
  </code></pre>
  
  <p>Views.py</p>
  
  <pre><code>def query1(request):
      air_list = Aircraft.objects.filter(commision_day__year__lte=(datetime.date.today().year - 10))
      #air_list = Aircraft.objects.extra(where=['commision_day + airplane_age &lt; CURDATE()'])
      #air_list = Aircraft.objects.extra(where=["commision_day+airplane_age&lt;datetime.date.today()"]) F('airplane_age') year=10, month=1, day=1
  </code></pre>
  
  <p>Data example</p>
  
  <pre><code>commision_day = 1995.10.05
  airplane_age = 15
  </code></pre>
  
  <p>I try many methods to do, but no one works((((<br>
  So i need to show plnes which commision day + airplane_age &lt; today day<br>
  Thanks</p>