Two Black Triangle UFOs Sighted Low Over Old Airfield and Village GB 10/11/16

I was advised by a friend at work to look up MUFON and report the UFO sighting we have had today 11/10/16 over our village of Grafton in Shropshire. Myself and 8 other friends were out walking along our local lanes and fields, and were heading back towards Grafton from the Montford Bridge area near Shrewsbury. At about 11:30 am we were walking towards Forton Heath Farm which is located alongside the old Forton Heath Airfield which is disused, when we all heard a loud humming sound. As we stopped and looked slightly to our left and to the North over the field that adjoins the airfield we saw two black triangle shaped UFOs low in the sky approaching the farm to the left of where we were standing our approx coordinates were 52.754036, -2.837602.
These two triangle type UFO things were really dark and solid and moved so slowly it was almost like they should fallen out of the sky. They were at about 500 ft my friend says and were moving alongside each other. We all stopped still trying to figure out what they were and two of my friends took their mobile phones out and took pictures (the images can be provided). As they did so both triangle started to shine red lights on the front and bottom of them. They then came to a hover about 200 yards from us, turned on a 360 and started to move back to the North but much quicker and with the same humming sound. They eventually disappeared from site and we couldn't hear them anymore either. One of the group with us is a recently retired police officer from West Mercia Police Force and he said that there is no way on earth that they were fast jets or drones, because jets and drone have loud audible engines that produce thrust and not a humming sound. He also said that the speed they were going defies all conventional means of moving through the air and he is dumbfounded as to what they could possibly be. We all agree that they are UFOs because they cannot be easily identified. We would like to know if anyone else has seen these strange looking things in Shropshire, and why they might of been lurking about over an old airfield etc? mufon cms# 79738