If you watch the radar you notice patterns with helicopters over London - there are vary distinct routes in the sky that they follow. Along the thames, and alon

If you watch the radar you notice patterns with helicopters over London - there are vary distinct routes in the sky that they follow. Along the thames, and along the M3 / M40. So seems an obvious extension of this sort of thing really. https://www.caa.co.uk/media/wppncpam/london-heli-route-chart.pdf https://www.caa.co.uk/media/wppncpam/london-heli-route-chart...