The best course if action I`ve determined is to constantly manufacture a MIG-32 Foxtrot, then equip it with some cheap rockets like Sidewinder and then sell it via "dismiss an airplane". You`ll also have 2 Mammoth heavy rockets in our storage s a bonus, $188k each.
But again you should be more or less rewarded for cleaning up all the survived aliens. Being able to sell (as opposed to use them) captured equipment and alien corpses is just a bonus.