The Americans are a law unto themselves because they can afford to be. Obama's big plan was for the US to end this unilateralism attitude and do things the UN way and abide by international law like a good citizen of the world eventually he learned the hard way he needs to take the traditional attitude of its the American way or its no way. Assuming its true and Iran shot down this UAV its not going to stop the US sending UAVS into Iran if it suits them, The US also has satellites spying on Iran 24/7/ so Iran watch out your American big brother is watching.
Yemen's Houthi rebels commit to peace plan in letter to UN chief, BBC reports (Haaretz)
from the article: Report: Iran shoots down U.S. reconnaissance drone