A male Ornate tailed diggerwasp (Cerceris rybyensis) foraging for nectar on Giant goldenrod (Solidago gigantea).
The photographs are unfortunately not that good.
I thought I had captured this particular specimen in the photos below for identification, see here, but the yellow colouring on tergites 4 and 5 is slightly different. Based on the characters it is the same species. Numerous Cerceris wasp species are flying on the Goldenrod and this day apparently this included at least two specimen of this species.
References1 Nederlands Soortenregister