"Complete and utter bollocks..."
I'll second that...
Boscombe Down is a very picturesque airfield in the middle of Wiltshire that trains test pilots and experiments with new equipment, including black projects. However, those black projects are simply black boxes on board existing aircraft. Do you really think that they are stupid enough to take-off and land black aircraft in full view of the second busiest road into the south-west of England, right next to a small town? You can't take off and land without flying straight over large numbers of inhabitants and/or flying through the approach corridors for Heathrow, Southampton, Bristol or Birmingham (let alone lesser but still active airfields)!
Aircrew killed following an undercarriage collapse? Is the author in the real world?
One minor detail that the author forgot was that the main Lockheed Martin site in the UK is just outside Portsmouth. Since Portsmouth doesn't have an active airfield anymore, the nearest one of any size is Southampton (see the comment about the ISVR - Institute of Sound and Vibration Research - at Southampton University).
So, an equally compelling theory is this: a Lockheed aircraft (for example, the SR
-71, even though it was 'officially' retired at that point - note than none of the 'observers' were close enough to give an accurate estimate of size) suffers a serious hydraulic failure and needs to make an emergency landing at a secure airfield. The only one in range is Boscombe. So, it lands on the downhill slope of the runway and, in the process, the nose undercarriage collapses. The Janet flight comes from Ramestein with engineers to assess the damage but they conclude that it can't be fixed in situ. The USAF
sends a C-5 to recover the damaged aircraft. Some of the 'boys' drop by to visit the Lockheed offices and ship the pilots home.
This is all crap and nothing to get worked up about. Conspiracy Theories are great, but when it's just the military not wanting to be too candid about their operations and co-operation with other nations, they are a waste of time. A bit like reading that article.
The definition of a 'Pessimist': an Optimist with experience...