Three Orbs over Alkmaar North Holland

I had just picked up my daughter from Egmond beach around 6:30pm, on my way back to Alkmaar we saw three very bright lights in the sky, they appeared to disappear and reappear repeatedly.

 I stopped the car and grabbed my camera, unfortunately my equipment leaves a lot to be desired (Sony Cyber Shot ).

The orbs where in a southerly position, the Sun had just set and the sky was cloudless and all three orbs appeared to disappear when an airplane approached! My daughter and two cow's in an adjacent field watched on in amusement!