Silicone mould for chocolate

[LakeFlyPie]

I want to make some chocolate aeroplanes for DS bday cake and have a small 5cm silicone mould.
Not really sure what I'm doing!
Do I need to temper the chocolate or can I just melt, pour in, chill and then pop out?
Not sure how I'm going to get it out without it snapping as it's pretty small and the tail of the plane looks relatively thin but deep