On the same day as our visit to Portmeirion we incorporated a detour to the Mach Loop (also known as the Machynlleth Loop) which is a series of valleys in the United Kingdom in west-central Wales, notable for their use as low-level training areas for fast jet aircraft and propeller-driven aircraft. Adrian is a keen plane spotter, but unfortunately we only saw a couple of trainers probably flying from Anglesey. en.wikipedia.org/wiki/RAF_Valley.

Here is what Adrian had hoped to see on the day: Low-level Flying Mach-Loop with some rare aircraft