Well how about kites?

http://vancouversun.com/news/national/high-flying-kite-1000-ft-in-the-air-causes-havoc-with-flights-in-victoria/wcm/6390bcb1-8027-4ad6-833d-ff8a5a51431f

Serious issue, in my country not only the drones, but one problem that is growing is persons pointing those laser pointers to the pilots in landing or takeoff, LPPT is in the middle of Lisbon city and it's easy to make this kind of stupid action

Here's recent's news about the subject: http://www.dnoticias.pt/pais/mais-de-1-150-casos-de-lasers-apontados-a-avioes-IE2336956#

who doens't understand Portuguese and wants to read please use the site below

http://itools.com/tool/google-translate-web-page-translator